diff --git a/forge-ai/src/main/java/forge/ai/ComputerUtilCard.java b/forge-ai/src/main/java/forge/ai/ComputerUtilCard.java
index 13e558ea7a9..61891b7ad87 100644
--- a/forge-ai/src/main/java/forge/ai/ComputerUtilCard.java
+++ b/forge-ai/src/main/java/forge/ai/ComputerUtilCard.java
@@ -643,7 +643,7 @@ public class ComputerUtilCard {
         return getMostProminentType(list, CardType.getAllCreatureTypes());
     }
 
-    public static String getMostProminentType(final CardCollectionView list, final List<String> valid) {
+    public static String getMostProminentType(final CardCollectionView list, final Collection<String> valid) {
         if (list.size() == 0) {
             return "";
         }
diff --git a/forge-ai/src/main/java/forge/ai/PlayerControllerAi.java b/forge-ai/src/main/java/forge/ai/PlayerControllerAi.java
index f0d1250cb58..04a9f303832 100644
--- a/forge-ai/src/main/java/forge/ai/PlayerControllerAi.java
+++ b/forge-ai/src/main/java/forge/ai/PlayerControllerAi.java
@@ -502,12 +502,11 @@ public class PlayerControllerAi extends PlayerController {
     }
 
     @Override
-    public String chooseSomeType(String kindOfType, SpellAbility sa, List<String> validTypes, List<String> invalidTypes, boolean isOptional) {
+    public String chooseSomeType(String kindOfType, SpellAbility sa, Collection<String> validTypes, List<String> invalidTypes, boolean isOptional) {
         String chosen = ComputerUtil.chooseSomeType(player, kindOfType, sa.getParam("AILogic"), invalidTypes);
-        if (StringUtils.isBlank(chosen) && !validTypes.isEmpty())
-        {
-            chosen = validTypes.get(0);
-            System.err.println("AI has no idea how to choose " + kindOfType +", defaulting to 1st element: chosen");
+        if (StringUtils.isBlank(chosen) && !validTypes.isEmpty()) {
+            chosen = validTypes.iterator().next();
+            System.err.println("AI has no idea how to choose " + kindOfType +", defaulting to arbitrary element: chosen");
         }
         game.getAction().nofityOfValue(sa, player, chosen, player);
         return chosen;
diff --git a/forge-core/src/main/java/forge/card/CardType.java b/forge-core/src/main/java/forge/card/CardType.java
index 21cd142f63a..fbc16fe6ad3 100644
--- a/forge-core/src/main/java/forge/card/CardType.java
+++ b/forge-core/src/main/java/forge/card/CardType.java
@@ -606,13 +606,13 @@ public final class CardType implements Comparable<CardType>, CardTypeView {
 
     public static class Constant {
         public static final Settable LOADED = new Settable();
-        public static final List<String> BASIC_TYPES = Lists.newArrayList();
-        public static final List<String> LAND_TYPES = Lists.newArrayList();
-        public static final List<String> CREATURE_TYPES = Lists.newArrayList();
-        public static final List<String> SPELL_TYPES = Lists.newArrayList();
-        public static final List<String> ENCHANTMENT_TYPES = Lists.newArrayList();
-        public static final List<String> ARTIFACT_TYPES = Lists.newArrayList();
-        public static final List<String> WALKER_TYPES = Lists.newArrayList();
+        public static final Set<String> BASIC_TYPES = Sets.newHashSet();
+        public static final Set<String> LAND_TYPES = Sets.newHashSet();
+        public static final Set<String> CREATURE_TYPES = Sets.newHashSet();
+        public static final Set<String> SPELL_TYPES = Sets.newHashSet();
+        public static final Set<String> ENCHANTMENT_TYPES = Sets.newHashSet();
+        public static final Set<String> ARTIFACT_TYPES = Sets.newHashSet();
+        public static final Set<String> WALKER_TYPES = Sets.newHashSet();
         
         // singular -> plural
         public static final BiMap<String,String> pluralTypes = HashBiMap.create();
@@ -699,12 +699,12 @@ public final class CardType implements Comparable<CardType>, CardTypeView {
         return sortedSubTypes;
     }
 
-    public static List<String> getBasicTypes() {
-        return Collections.unmodifiableList(Constant.BASIC_TYPES);
+    public static Collection<String> getBasicTypes() {
+        return Collections.unmodifiableCollection(Constant.BASIC_TYPES);
     }
 
-    public static List<String> getAllCreatureTypes() {
-        return Collections.unmodifiableList(Constant.CREATURE_TYPES);
+    public static Collection<String> getAllCreatureTypes() {
+        return Collections.unmodifiableCollection(Constant.CREATURE_TYPES);
     }
     public static List<String> getAllLandTypes() {
         return ImmutableList.<String>builder()
diff --git a/forge-game/src/main/java/forge/game/CardTraitBase.java b/forge-game/src/main/java/forge/game/CardTraitBase.java
index 34c2a77edf5..a17f64007ae 100644
--- a/forge-game/src/main/java/forge/game/CardTraitBase.java
+++ b/forge-game/src/main/java/forge/game/CardTraitBase.java
@@ -73,7 +73,7 @@ public abstract class CardTraitBase extends GameObject implements IHasCardView {
     }
 
     public final String getParamOrDefault(String key, String defaultValue) {
-        return hasParam(key) ? getParam(key) : defaultValue;
+        return mapParams.getOrDefault(key, defaultValue);
     }
 
     public String getParam(String key) {
diff --git a/forge-game/src/main/java/forge/game/player/PlayerController.java b/forge-game/src/main/java/forge/game/player/PlayerController.java
index d5cef95818b..62d57539212 100644
--- a/forge-game/src/main/java/forge/game/player/PlayerController.java
+++ b/forge-game/src/main/java/forge/game/player/PlayerController.java
@@ -161,8 +161,8 @@ public abstract class PlayerController {
     public abstract List<SpellAbility> chooseSaToActivateFromOpeningHand(List<SpellAbility> usableFromOpeningHand);
     public abstract Mana chooseManaFromPool(List<Mana> manaChoices);
 
-    public abstract String chooseSomeType(String kindOfType, SpellAbility sa, List<String> validTypes, List<String> invalidTypes, boolean isOptional);
-    public final String chooseSomeType(String kindOfType, SpellAbility sa, List<String> validTypes, List<String> invalidTypes) {
+    public abstract String chooseSomeType(String kindOfType, SpellAbility sa, Collection<String> validTypes, List<String> invalidTypes, boolean isOptional);
+    public final String chooseSomeType(String kindOfType, SpellAbility sa, Collection<String> validTypes, List<String> invalidTypes) {
         return chooseSomeType(kindOfType, sa, validTypes, invalidTypes, false);
     }
 
diff --git a/forge-gui-desktop/src/test/java/forge/gamesimulationtests/util/PlayerControllerForTests.java b/forge-gui-desktop/src/test/java/forge/gamesimulationtests/util/PlayerControllerForTests.java
index f1906ebdb0f..c9ee0f75d17 100644
--- a/forge-gui-desktop/src/test/java/forge/gamesimulationtests/util/PlayerControllerForTests.java
+++ b/forge-gui-desktop/src/test/java/forge/gamesimulationtests/util/PlayerControllerForTests.java
@@ -481,7 +481,7 @@ public class PlayerControllerForTests extends PlayerController {
     }
 
     @Override
-    public String chooseSomeType(String kindOfType, SpellAbility sa, List<String> validTypes, List<String> invalidTypes, boolean isOptional) {
+    public String chooseSomeType(String kindOfType, SpellAbility sa, Collection<String> validTypes, List<String> invalidTypes, boolean isOptional) {
         return chooseItem(validTypes);
     }
 
diff --git a/forge-gui/src/main/java/forge/model/FModel.java b/forge-gui/src/main/java/forge/model/FModel.java
index 27d0060413c..d0c182e890c 100644
--- a/forge-gui/src/main/java/forge/model/FModel.java
+++ b/forge-gui/src/main/java/forge/model/FModel.java
@@ -57,6 +57,7 @@ import forge.util.storage.StorageBase;
 import java.io.File;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * The default Model implementation for Forge.
@@ -259,31 +260,31 @@ public final class FModel {
         if (!CardType.Constant.LOADED.isSet()) {
             final List<String> typeListFile = FileUtil.readFile(ForgeConstants.TYPE_LIST_FILE);
 
-            List<String> tList = null;
+            Set<String> addTo = null;
 
             for (final String s : typeListFile) {
                 if (s.equals("[BasicTypes]")) {
-                    tList = CardType.Constant.BASIC_TYPES;
+                    addTo = CardType.Constant.BASIC_TYPES;
                 } else if (s.equals("[LandTypes]")) {
-                    tList = CardType.Constant.LAND_TYPES;
+                    addTo = CardType.Constant.LAND_TYPES;
                 } else if (s.equals("[CreatureTypes]")) {
-                    tList = CardType.Constant.CREATURE_TYPES;
+                    addTo = CardType.Constant.CREATURE_TYPES;
                 } else if (s.equals("[SpellTypes]")) {
-                    tList = CardType.Constant.SPELL_TYPES;
+                    addTo = CardType.Constant.SPELL_TYPES;
                 } else if (s.equals("[EnchantmentTypes]")) {
-                    tList = CardType.Constant.ENCHANTMENT_TYPES;
+                    addTo = CardType.Constant.ENCHANTMENT_TYPES;
                 } else if (s.equals("[ArtifactTypes]")) {
-                    tList = CardType.Constant.ARTIFACT_TYPES;
+                    addTo = CardType.Constant.ARTIFACT_TYPES;
                 } else if (s.equals("[WalkerTypes]")) {
-                    tList = CardType.Constant.WALKER_TYPES;
+                    addTo = CardType.Constant.WALKER_TYPES;
                 } else if (s.length() > 1) {
-                    if (tList != null) {
+                    if (addTo != null) {
                         if (s.contains(":")) {
                             String[] k = s.split(":");
-                            tList.add(k[0]);
+                            addTo.add(k[0]);
                             CardType.Constant.pluralTypes.put(k[0], k[1]);
                         } else {
-                            tList.add(s);
+                            addTo.add(s);
                         }
                     }
                 }
diff --git a/forge-gui/src/main/java/forge/player/PlayerControllerHuman.java b/forge-gui/src/main/java/forge/player/PlayerControllerHuman.java
index 053e152fd11..45361909b01 100644
--- a/forge-gui/src/main/java/forge/player/PlayerControllerHuman.java
+++ b/forge-gui/src/main/java/forge/player/PlayerControllerHuman.java
@@ -1034,7 +1034,7 @@ public class PlayerControllerHuman extends PlayerController implements IGameCont
      * java.lang.String, java.util.List, java.util.List, java.lang.String)
      */
     @Override
-    public String chooseSomeType(final String kindOfType, final SpellAbility sa, final List<String> validTypes,
+    public String chooseSomeType(final String kindOfType, final SpellAbility sa, final Collection<String> validTypes,
             final List<String> invalidTypes, final boolean isOptional) {
         final List<String> types = Lists.newArrayList(validTypes);
         if (invalidTypes != null && !invalidTypes.isEmpty()) {