diff --git a/cockatrice/src/interface/card_picture_loader/card_picture_to_load.cpp b/cockatrice/src/interface/card_picture_loader/card_picture_to_load.cpp
index e35c417c8..8e8feb5b5 100644
--- a/cockatrice/src/interface/card_picture_loader/card_picture_to_load.cpp
+++ b/cockatrice/src/interface/card_picture_loader/card_picture_to_load.cpp
@@ -21,6 +21,7 @@
 #include <libcockatrice/interfaces/noop_card_set_priority_controller.h>
 #include <libcockatrice/settings/cards_display_settings.h>
 #include <libcockatrice/settings/download_settings.h>
+#include <utility>
 
 CardPictureToLoad::CardPictureToLoad(const ExactCard &_card)
     : card(_card), urlTemplates(SettingsCache::instance().downloads().getAllURLs())
@@ -74,19 +75,20 @@ QList<CardSetPtr> CardPictureToLoad::extractSetsSorted(const ExactCard &card)
 //! \todo Check if going through all sets is still necessary after the ExactCard refactor.
 static PrintingInfo findPrintingForSet(const ExactCard &card, const QString &setName)
 {
-    SetToPrintingsMap setsToPrintings = card.getInfo().getSets();
+    const auto &setsToPrintings = card.getInfo().getSets();
 
-    if (!setsToPrintings.contains(setName)) {
+    const auto setPrintings = setsToPrintings.constFind(setName);
+    if (setPrintings == setsToPrintings.constEnd() || setPrintings.value().isEmpty()) {
         return PrintingInfo();
     }
 
-    for (const auto &printing : setsToPrintings[setName]) {
+    for (const auto &printing : setPrintings.value()) {
         if (printing.getUuid() == card.getPrinting().getUuid()) {
             return printing;
         }
     }
 
-    return setsToPrintings[setName][0];
+    return setPrintings.value().first();
 }
 
 void CardPictureToLoad::populateSetUrls()
@@ -183,10 +185,14 @@ static int parse(const QString &urlTemplate,
 {
     static const QRegularExpression rxFillWith("^(.+)_fill_with_(.+)$");
     static const QRegularExpression rxSubStr("^(.+)_substr_(\\d+)_(\\d+)$");
+    static const QRegularExpression rxCardProp("!prop:([^!]+)!");
+    static const QRegularExpression rxCardSet("!set:([^!]+)!");
 
-    const QRegularExpression rxCardProp("!" + propType + ":([^!]+)!");
+    // The property type only takes two values, so keep the expression that was
+    // compiled for it instead of rebuilding one per URL template.
+    const QRegularExpression &rxCardPropSelector = propType == "prop" ? rxCardProp : rxCardSet;
 
-    auto matches = rxCardProp.globalMatch(urlTemplate);
+    auto matches = rxCardPropSelector.globalMatch(urlTemplate);
     while (matches.hasNext()) {
         auto match = matches.next();
         QString templatePropertyName = match.captured(1);
@@ -303,10 +309,10 @@ QString CardPictureToLoad::transformUrl(const QString &urlTemplate) const
     }
 
     QString transformedUrl = urlTemplate;
-    for (const QString &prop : transformMap.keys()) {
+    for (const auto &[prop, value] : std::as_const(transformMap).asKeyValueRange()) {
         if (transformedUrl.contains(prop)) {
-            if (!transformMap[prop].isEmpty()) {
-                transformedUrl.replace(prop, QUrl::toPercentEncoding(transformMap[prop]));
+            if (!value.isEmpty()) {
+                transformedUrl.replace(prop, QUrl::toPercentEncoding(value));
             } else {
                 /* This means the template is requesting information that is not
                  * populated in this card, so it should return an empty string,
diff --git a/cockatrice/src/interface/widgets/dialogs/dlg_select_set_for_cards.cpp b/cockatrice/src/interface/widgets/dialogs/dlg_select_set_for_cards.cpp
index 55c6569f7..57ea09628 100644
--- a/cockatrice/src/interface/widgets/dialogs/dlg_select_set_for_cards.cpp
+++ b/cockatrice/src/interface/widgets/dialogs/dlg_select_set_for_cards.cpp
@@ -274,9 +274,9 @@ QMap<QString, int> DlgSelectSetForCards::getSetsForCards()
             continue;
         }
 
-        SetToPrintingsMap setMap = infoPtr->getSets();
-        for (auto &setName : setMap.keys()) {
-            setCounts[setName]++;
+        const auto &setMap = infoPtr->getSets();
+        for (auto it = setMap.constBegin(); it != setMap.constEnd(); ++it) {
+            setCounts[it.key()]++;
         }
     }
 
@@ -393,8 +393,8 @@ QMap<QString, QStringList> DlgSelectSetForCards::getCardsForSets()
             continue;
         }
 
-        SetToPrintingsMap setMap = infoPtr->getSets();
-        for (auto it = setMap.begin(); it != setMap.end(); ++it) {
+        const auto &setMap = infoPtr->getSets();
+        for (auto it = setMap.constBegin(); it != setMap.constEnd(); ++it) {
             setCards[it.key()].append(cardName);
         }
     }
diff --git a/cockatrice/src/interface/widgets/printing_selector/printing_selector.cpp b/cockatrice/src/interface/widgets/printing_selector/printing_selector.cpp
index 27ae61b94..983d6ba32 100644
--- a/cockatrice/src/interface/widgets/printing_selector/printing_selector.cpp
+++ b/cockatrice/src/interface/widgets/printing_selector/printing_selector.cpp
@@ -229,7 +229,7 @@ void PrintingSelector::getAllSetsForCurrentCard()
         return;
     }
 
-    SetToPrintingsMap setMap = selectedCard->getSets();
+    const auto &setMap = selectedCard->getSets();
     const QList<PrintingInfo> sortedPrintings = sortToolBar->sortSets(setMap);
     const QList<PrintingInfo> filteredPrintings =
         sortToolBar->filterSets(sortedPrintings, searchBar->getSearchText().trimmed().toLower());
diff --git a/cockatrice/src/interface/widgets/printing_selector/printing_selector_card_sorting_widget.cpp b/cockatrice/src/interface/widgets/printing_selector/printing_selector_card_sorting_widget.cpp
index f47ba0746..1cd372259 100644
--- a/cockatrice/src/interface/widgets/printing_selector/printing_selector_card_sorting_widget.cpp
+++ b/cockatrice/src/interface/widgets/printing_selector/printing_selector_card_sorting_widget.cpp
@@ -208,7 +208,7 @@ QList<PrintingInfo> PrintingSelectorCardSortingWidget::prependPrintingsInDeck(co
         return {};
     }
 
-    SetToPrintingsMap setMap = selectedCard->getSets();
+    const auto &setMap = selectedCard->getSets();
     QList<QPair<PrintingInfo, int>> countList;
 
     // Collect sets with their counts
diff --git a/cockatrice/src/interface/widgets/visual_database_display/visual_database_display_widget.cpp b/cockatrice/src/interface/widgets/visual_database_display/visual_database_display_widget.cpp
index 599ac97b4..1a54ff0f5 100644
--- a/cockatrice/src/interface/widgets/visual_database_display/visual_database_display_widget.cpp
+++ b/cockatrice/src/interface/widgets/visual_database_display/visual_database_display_widget.cpp
@@ -432,10 +432,11 @@ void VisualDatabaseDisplayWidget::loadPage(int start, int end)
 
         if (CardInfoPtr info = CardDatabaseManager::query()->getCardInfo(name.toString())) {
             if (!setFilters.empty()) {
-                SetToPrintingsMap setMap = info->getSets();
+                const auto &setMap = info->getSets();
                 for (const CardFilter *setFilter : setFilters) {
-                    if (setMap.contains(setFilter->term())) {
-                        for (PrintingInfo printing : setMap[setFilter->term()]) {
+                    const auto it = setMap.constFind(setFilter->term());
+                    if (it != setMap.constEnd()) {
+                        for (const PrintingInfo &printing : it.value()) {
                             addCardToDisplay(ExactCard(info, printing));
                         }
                     }
diff --git a/libcockatrice_card/libcockatrice/card/card_info.cpp b/libcockatrice_card/libcockatrice/card/card_info.cpp
index bd33f18e7..ae2382166 100644
--- a/libcockatrice_card/libcockatrice/card/card_info.cpp
+++ b/libcockatrice_card/libcockatrice/card/card_info.cpp
@@ -245,7 +245,7 @@ QString CardInfo::simplifyName(const QString &name)
 
 QChar CardInfo::getColorChar() const
 {
-    QString colors = getColors();
+    const QString colors = getColors();
     switch (colors.size()) {
         case 0:
             return QChar();
diff --git a/libcockatrice_card/libcockatrice/card/card_info.h b/libcockatrice_card/libcockatrice/card/card_info.h
index 356da0546..c0dccb885 100644
--- a/libcockatrice_card/libcockatrice/card/card_info.h
+++ b/libcockatrice_card/libcockatrice/card/card_info.h
@@ -280,7 +280,7 @@ public:
     {
         return simpleName;
     }
-    const QSet<QString> &getAltNames()
+    const QSet<QString> &getAltNames() const
     {
         return altNames;
     }
@@ -395,7 +395,9 @@ public:
 
     [[nodiscard]] QString getProperty(const QString &propertyName) const
     {
-        return getPropertiesHash().value(propertyName);
+        const auto &propertiesHash = getPropertiesHash();
+        const auto it = propertiesHash.constFind(propertyName);
+        return it != propertiesHash.constEnd() ? it.value() : QString();
     }
     void setProperty(const QString &_name, const QString &_value);
     [[nodiscard]] bool hasProperty(const QString &propertyName) const
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_cache.cpp b/libcockatrice_card/libcockatrice/card/database/card_database_cache.cpp
index 4ab4d1fca..42658dd6b 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database_cache.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_cache.cpp
@@ -210,7 +210,7 @@ void writeCard(QDataStream &out, const CardInfoPtr &card)
     // per-printing alt-name scan entirely.
     writeString(out, card->getSimpleName());
     {
-        const QSet<QString> altNames = card->getAltNames();
+        const QSet<QString> &altNames = card->getAltNames();
         out << static_cast<quint32>(altNames.size());
         for (const QString &alt : altNames) {
             writeString(out, alt);
@@ -218,7 +218,7 @@ void writeCard(QDataStream &out, const CardInfoPtr &card)
     }
 
     // setsToPrintings
-    const SetToPrintingsMap sets = card->getSets();
+    const auto &sets = card->getSets();
     out << static_cast<quint32>(sets.size());
     for (auto it = sets.constBegin(); it != sets.constEnd(); ++it) {
         writeString(out, it.key());
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_querier.cpp b/libcockatrice_card/libcockatrice/card/database/card_database_querier.cpp
index 7c41daa3b..8df0d2e20 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database_querier.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_querier.cpp
@@ -12,6 +12,7 @@
 #include <QRandomGenerator>
 #include <QSharedPointer>
 #include <QStringLiteral>
+#include <iterator>
 #include <qnamespace.h>
 
 CardDatabaseQuerier::CardDatabaseQuerier(QObject *_parent,
@@ -52,6 +53,7 @@ CardInfoPtr CardDatabaseQuerier::getCardInfo(const QString &cardName) const
 QList<CardInfoPtr> CardDatabaseQuerier::getCardInfos(const QStringList &cardNames) const
 {
     QList<CardInfoPtr> cardInfos;
+    cardInfos.reserve(cardNames.size());
     for (const QString &cardName : cardNames) {
         CardInfoPtr ptr = db->cards.value(cardName);
         if (ptr) {
@@ -90,6 +92,7 @@ CardInfoPtr CardDatabaseQuerier::lookupCardByName(const QString &name) const
 QList<ExactCard> CardDatabaseQuerier::getCards(const QList<CardRef> &cardRefs) const
 {
     QList<ExactCard> cards;
+    cards.reserve(cardRefs.size());
     for (const auto &cardRef : cardRefs) {
         ExactCard card = getCard(cardRef);
         if (card) {
@@ -149,10 +152,10 @@ ExactCard CardDatabaseQuerier::getRandomCard() const
         return {};
     }
 
-    const auto keys = db->cards.keys();
-    int randomIndex = QRandomGenerator::global()->bounded(keys.size());
-    const QString &randomKey = keys.at(randomIndex);
-    CardInfoPtr randomCard = getCardInfo(randomKey);
+    const auto randomIndex = QRandomGenerator::global()->bounded(db->cards.size());
+    auto it = db->cards.constBegin();
+    std::advance(it, randomIndex);
+    CardInfoPtr randomCard = it.value();
 
     return ExactCard{randomCard, getPreferredPrinting(randomCard)};
 }
@@ -215,20 +218,23 @@ PrintingInfo CardDatabaseQuerier::getSpecificPrinting(const QString &cardName,
         return PrintingInfo(nullptr);
     }
 
-    SetToPrintingsMap setMap = cardInfo->getSets();
+    const auto &setMap = cardInfo->getSets();
     if (setMap.empty()) {
         return PrintingInfo(nullptr);
     }
 
     for (const auto &printings : setMap) {
-        for (auto &cardInfoForSet : printings) {
+        for (const auto &cardInfoForSet : printings) {
+            const CardSetPtr &set = cardInfoForSet.getSet();
+            if (!set) {
+                continue;
+            }
             if (!collectorNumber.isEmpty()) {
-                if (cardInfoForSet.getSet()->getShortName() == setShortName &&
-                    cardInfoForSet.getProperty("num") == collectorNumber) {
+                if (set->getShortName() == setShortName && cardInfoForSet.getProperty("num") == collectorNumber) {
                     return cardInfoForSet;
                 }
             } else {
-                if (cardInfoForSet.getSet()->getShortName() == setShortName) {
+                if (set->getShortName() == setShortName) {
                     return cardInfoForSet;
                 }
             }
@@ -284,10 +290,10 @@ PrintingInfo CardDatabaseQuerier::getPreferredPrinting(const CardInfoPtr &cardIn
     const auto &pinnedPrintingProviderId = prefs->getCardPreferenceOverride(cardInfo->getName());
 
     if (!pinnedPrintingProviderId.isEmpty()) {
-        return getSpecificPrinting({cardInfo->getName(), pinnedPrintingProviderId});
+        return findPrintingWithId(cardInfo, pinnedPrintingProviderId);
     }
 
-    SetToPrintingsMap setMap = cardInfo->getSets();
+    const auto &setMap = cardInfo->getSets();
     if (setMap.empty()) {
         return PrintingInfo(nullptr);
     }
@@ -297,8 +303,8 @@ PrintingInfo CardDatabaseQuerier::getPreferredPrinting(const CardInfoPtr &cardIn
     SetPriorityComparator comparator;
 
     for (const auto &printings : setMap) {
-        for (auto &printing : printings) {
-            CardSetPtr currentSet = printing.getSet();
+        for (const auto &printing : printings) {
+            const CardSetPtr &currentSet = printing.getSet();
             if (!preferredSet || comparator(currentSet, preferredSet)) {
                 preferredSet = currentSet;
                 preferredPrinting = printing;
@@ -315,17 +321,18 @@ PrintingInfo CardDatabaseQuerier::getPreferredPrinting(const CardInfoPtr &cardIn
 
 QString CardDatabaseQuerier::getPreferredPrintingProviderId(const QString &cardName) const
 {
-    PrintingInfo preferredPrinting = getPreferredPrinting(cardName);
-    QString uuid = preferredPrinting.getUuid();
+    CardInfoPtr cardInfo = getCardInfo(cardName);
+    if (!cardInfo) {
+        return cardName;
+    }
+
+    PrintingInfo preferredPrinting = getPreferredPrinting(cardInfo);
+    const QString &uuid = preferredPrinting.getUuid();
     if (!uuid.isEmpty()) {
         return uuid;
     }
 
-    CardInfoPtr defaultCardInfo = getCardInfo(cardName);
-    if (defaultCardInfo.isNull()) {
-        return cardName;
-    }
-    return defaultCardInfo->getName();
+    return cardInfo->getName();
 }
 
 QStringList CardDatabaseQuerier::getAllMainCardTypes() const
@@ -339,8 +346,8 @@ QMap<QString, int> CardDatabaseQuerier::getAllMainCardTypesWithCount() const
     // produces an empty map, so the cache is only ever empty when it needs a
     // (trivially cheap) rebuild.
     if (mainCardTypeCountsCache.isEmpty()) {
-        for (const auto &card : db->cards.values()) {
-            QString type = card->getMainCardType();
+        for (const auto &card : db->cards) {
+            const QString type = card->getMainCardType();
             mainCardTypeCountsCache[type]++;
         }
     }
@@ -351,13 +358,13 @@ QMap<QString, int> CardDatabaseQuerier::getAllMainCardTypesWithCount() const
 QMap<QString, int> CardDatabaseQuerier::getAllSubCardTypesWithCount() const
 {
     if (subCardTypeCountsCache.isEmpty()) {
-        for (const auto &card : db->cards.values()) {
-            QString type = card->getCardType();
+        for (const auto &card : db->cards) {
+            const QString type = card->getCardType();
 
-            QStringList parts = type.split(" — ");
+            const QStringList parts = type.split(" — ");
 
             if (parts.size() > 1) { // Ensure there are subtypes
-                QStringList subtypes = parts[1].split(" ", Qt::SkipEmptyParts);
+                const QStringList subtypes = parts[1].split(" ", Qt::SkipEmptyParts);
 
                 for (const QString &subtype : subtypes) {
                     subCardTypeCountsCache[subtype]++;
@@ -377,13 +384,13 @@ FormatRulesPtr CardDatabaseQuerier::getFormat(const QString &formatName) const
 QMap<QString, int> CardDatabaseQuerier::getAllFormatsWithCount() const
 {
     if (formatsCountCache.isEmpty()) {
-        for (const auto &card : db->cards.values()) {
-            QStringList allProps = card->getProperties();
+        static const QString formatPrefix = QStringLiteral("format-");
 
-            for (const QString &prop : allProps) {
-                if (prop.startsWith("format-")) {
-                    QString formatName = prop.mid(QStringLiteral("format-").size());
-                    formatsCountCache[formatName]++;
+        for (const auto &card : db->cards) {
+            const auto &properties = card->getPropertiesHash();
+            for (auto it = properties.constBegin(); it != properties.constEnd(); ++it) {
+                if (it.key().startsWith(formatPrefix)) {
+                    formatsCountCache[it.key().mid(formatPrefix.size())]++;
                 }
             }
         }
diff --git a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp
index b17eb8b5e..33a0e0849 100644
--- a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp
@@ -401,7 +401,7 @@ static QXmlStreamWriter &operator<<(QXmlStreamWriter &xml, const CardInfoPtr &in
     }
 
     // sets
-    const SetToPrintingsMap setMap = info->getSets();
+    const auto &setMap = info->getSets();
     for (const auto &printings : setMap) {
         for (const PrintingInfo &set : printings) {
             xml.writeStartElement("set");
diff --git a/libcockatrice_card/libcockatrice/card/lazy_properties_hash.cpp b/libcockatrice_card/libcockatrice/card/lazy_properties_hash.cpp
index a12de469b..90628224a 100644
--- a/libcockatrice_card/libcockatrice/card/lazy_properties_hash.cpp
+++ b/libcockatrice_card/libcockatrice/card/lazy_properties_hash.cpp
@@ -20,15 +20,15 @@ LazyPropertiesHash::LazyPropertiesHash(const QHash<QString, QString> &properties
 LazyPropertiesHash::LazyPropertiesHash(const LazyPropertiesHash &other)
 {
     // since we do not allow dematerialization, we only need to lock if not materialized yet
-    if (other.isMaterialized) {
+    if (other.isMaterialized.load(std::memory_order_acquire)) {
         blob = other.blob;
         properties = other.properties;
-        isMaterialized = true;
+        isMaterialized.store(true, std::memory_order_relaxed);
     } else {
         QMutexLocker lock(&other.propertiesMutex);
         blob = other.blob;
         properties = other.properties;
-        isMaterialized = false;
+        isMaterialized.store(other.isMaterialized.load(std::memory_order_relaxed), std::memory_order_relaxed);
     }
 }
 
@@ -39,15 +39,15 @@ LazyPropertiesHash &LazyPropertiesHash::operator=(const LazyPropertiesHash &othe
     }
 
     // since we do not allow dematerialization, we only need to lock if not materialized yet
-    if (other.isMaterialized) {
+    if (other.isMaterialized.load(std::memory_order_acquire)) {
         blob = other.blob;
         properties = other.properties;
-        isMaterialized = true;
+        isMaterialized.store(true, std::memory_order_relaxed);
     } else {
         QMutexLocker lock(&other.propertiesMutex);
         blob = other.blob;
         properties = other.properties;
-        isMaterialized = false;
+        isMaterialized.store(false, std::memory_order_relaxed);
     }
 
     return *this;
@@ -55,9 +55,15 @@ LazyPropertiesHash &LazyPropertiesHash::operator=(const LazyPropertiesHash &othe
 
 void LazyPropertiesHash::ensureMaterialized() const
 {
+    // Materialization happens once and is never undone, so the common case can
+    // skip the mutex entirely once it has happened.
+    if (isMaterialized.load(std::memory_order_acquire)) {
+        return;
+    }
+
     QMutexLocker lock(&propertiesMutex);
 
-    if (isMaterialized) {
+    if (isMaterialized.load(std::memory_order_relaxed)) {
         return;
     }
 
@@ -69,7 +75,7 @@ void LazyPropertiesHash::ensureMaterialized() const
 
     blob.clear();
 
-    isMaterialized = true;
+    isMaterialized.store(true, std::memory_order_release);
 }
 
 QString LazyPropertiesHash::value(const QString &key) const
diff --git a/libcockatrice_card/libcockatrice/card/lazy_properties_hash.h b/libcockatrice_card/libcockatrice/card/lazy_properties_hash.h
index 04f5d0251..9e34050e5 100644
--- a/libcockatrice_card/libcockatrice/card/lazy_properties_hash.h
+++ b/libcockatrice_card/libcockatrice/card/lazy_properties_hash.h
@@ -5,6 +5,7 @@
 #include <QHash>
 #include <QMutex>
 #include <QString>
+#include <atomic>
 
 /**
  * @brief A property map that can lazily deserialize blobs to avoid loading overhead.
@@ -18,10 +19,10 @@
 class LazyPropertiesHash
 {
 
-    mutable QByteArray blob;                    ///< Serialized properties (load form).
-    mutable QHash<QString, QString> properties; ///< Materialized properties (query form).
-    mutable QMutex propertiesMutex;             ///< Guards lazy materialization.
-    mutable bool isMaterialized = false;        ///< Whether propertiesCache is valid.
+    mutable QByteArray blob;                         ///< Serialized properties (load form).
+    mutable QHash<QString, QString> properties;      ///< Materialized properties (query form).
+    mutable QMutex propertiesMutex;                  ///< Guards lazy materialization.
+    mutable std::atomic<bool> isMaterialized{false}; ///< Whether properties is valid.
 
     /**
      * @brief Materializes properties from blob if not already done. Clears blob afterward.
diff --git a/libcockatrice_card/libcockatrice/card/printing/exact_card.h b/libcockatrice_card/libcockatrice/card/printing/exact_card.h
index ea49072fb..83ba97bd0 100644
--- a/libcockatrice_card/libcockatrice/card/printing/exact_card.h
+++ b/libcockatrice_card/libcockatrice/card/printing/exact_card.h
@@ -47,7 +47,7 @@ public:
      *
      * May be null if the ExactCard is empty.
      */
-    [[nodiscard]] CardInfoPtr getCardPtr() const
+    [[nodiscard]] const CardInfoPtr &getCardPtr() const
     {
         return card;
     }
@@ -57,7 +57,7 @@ public:
      *
      * May be empty if no specific printing was assigned.
      */
-    [[nodiscard]] PrintingInfo getPrinting() const
+    [[nodiscard]] const PrintingInfo &getPrinting() const
     {
         return printing;
     }
diff --git a/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp b/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp
index 654efac5e..9440eb4b0 100644
--- a/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp
+++ b/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp
@@ -17,10 +17,10 @@ void PrintingInfo::setProperty(const QString &_name, const QString &_value)
  */
 QString PrintingInfo::getUuid() const
 {
-    return getPropertiesHash().value("uuid");
+    return getProperty("uuid");
 }
 
 QString PrintingInfo::getFlavorName() const
 {
-    return getPropertiesHash().value("flavorName");
+    return getProperty("flavorName");
 }
diff --git a/libcockatrice_card/libcockatrice/card/printing/printing_info.h b/libcockatrice_card/libcockatrice/card/printing/printing_info.h
index 038960e86..75f634c3c 100644
--- a/libcockatrice_card/libcockatrice/card/printing/printing_info.h
+++ b/libcockatrice_card/libcockatrice/card/printing/printing_info.h
@@ -107,7 +107,9 @@ public:
      */
     [[nodiscard]] QString getProperty(const QString &propertyName) const
     {
-        return properties.value(propertyName);
+        const auto &propertiesHash = getPropertiesHash();
+        const auto it = propertiesHash.constFind(propertyName);
+        return it != propertiesHash.constEnd() ? it.value() : QString();
     }
 
     /**
diff --git a/libcockatrice_card/libcockatrice/card/set/card_set.cpp b/libcockatrice_card/libcockatrice/card/set/card_set.cpp
index e873eeeab..e2b41a811 100644
--- a/libcockatrice_card/libcockatrice/card/set/card_set.cpp
+++ b/libcockatrice_card/libcockatrice/card/set/card_set.cpp
@@ -34,10 +34,14 @@ CardSetPtr CardSet::newInstance(ICardSetPriorityController *_priorityController,
 QString CardSet::getCorrectedShortName() const
 {
     // For Windows machines.
-    QSet<QString> invalidFileNames;
-    invalidFileNames << "CON" << "PRN" << "AUX" << "NUL" << "COM1" << "COM2" << "COM3" << "COM4" << "COM5" << "COM6"
-                     << "COM7" << "COM8" << "COM9" << "LPT1" << "LPT2" << "LPT3" << "LPT4" << "LPT5" << "LPT6" << "LPT7"
-                     << "LPT8" << "LPT9";
+    static const QSet<QString> invalidFileNames = {
+        QStringLiteral("CON"),  QStringLiteral("PRN"),  QStringLiteral("AUX"),  QStringLiteral("NUL"),
+        QStringLiteral("COM1"), QStringLiteral("COM2"), QStringLiteral("COM3"), QStringLiteral("COM4"),
+        QStringLiteral("COM5"), QStringLiteral("COM6"), QStringLiteral("COM7"), QStringLiteral("COM8"),
+        QStringLiteral("COM9"), QStringLiteral("LPT1"), QStringLiteral("LPT2"), QStringLiteral("LPT3"),
+        QStringLiteral("LPT4"), QStringLiteral("LPT5"), QStringLiteral("LPT6"), QStringLiteral("LPT7"),
+        QStringLiteral("LPT8"), QStringLiteral("LPT9"),
+    };
 
     return invalidFileNames.contains(shortName) ? shortName + "_" : shortName;
 }
diff --git a/libcockatrice_card/libcockatrice/card/set/card_set.h b/libcockatrice_card/libcockatrice/card/set/card_set.h
index b9ac74e2d..b995ac88e 100644
--- a/libcockatrice_card/libcockatrice/card/set/card_set.h
+++ b/libcockatrice_card/libcockatrice/card/set/card_set.h
@@ -239,7 +239,7 @@ public:
      */
     [[nodiscard]] bool getIsKnownIgnored() const
     {
-        return longName.length() + setType.length() + releaseDate.toString().length() == 0;
+        return longName.isEmpty() && setType.isEmpty() && !releaseDate.isValid();
     }
 };