Adding to cards where needed (and removing from cards where it isn't safe to rely on one copy, like Moat)

forge-gui/res/cardsfolder/p/peace_of_mind.txt

@@ -5,5 +5,6 @@ A:AB$ GainLife | Cost$ W Discard<1/Card> | LifeAmount$ 3 | SpellDescription$ You
 SVar:AIPreference:DiscardCost$Card
 DeckHints:Ability$Discard
 SVar:RemRandomDeck:True
+SVar:NonStackingEffect:True
 SVar:Picture:http://www.wizards.com/global/images/magic/general/peace_of_mind.jpg
 Oracle:{W}, Discard a card: You gain 3 life.

forge-gui/res/cardsfolder/p/pestilence.txt

@@ -5,5 +5,6 @@ T:Mode$ Phase | Phase$ End of Turn | TriggerZones$ Battlefield | IsPresent$ Crea
 SVar:TrigSac:DB$Sacrifice | Defined$ Self
 A:AB$ DamageAll | Cost$ B | NumDmg$ 1 | ValidCards$ Creature | ValidPlayers$ Player | ValidDescription$ each creature and each player. | AILogic$ DmgAllCreaturesAndPlayers | SpellDescription$ CARDNAME deals 1 damage to each creature and each player.
 SVar:NeedsToPlay:Creature
+SVar:NonStackingEffect:True
 SVar:Picture:http://resources.wizards.com/magic/cards/uz/en-us/card5619.jpg
 Oracle:At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.\n{B}: Pestilence deals 1 damage to each creature and each player.

forge-gui/res/cardsfolder/p/presence_of_the_master.txt

@@ -5,5 +5,6 @@ T:Mode$ SpellCast | ValidCard$ Enchantment | TriggerZones$ Battlefield | Execute
 SVar:TrigCounter:DB$Counter | Defined$ TriggeredSpellAbility
 SVar:AICurseEffect:CounterEnchantment
 SVar:RemRandomDeck:True
+SVar:NonStackingEffect:True
 SVar:Picture:http://www.wizards.com/global/images/magic/general/presence_of_the_master.jpg
 Oracle:Whenever a player casts an enchantment spell, counter it.