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/m/mind_slash.txt

@@ -3,5 +3,6 @@ ManaCost:1 B B
 Types:Enchantment
 A:AB$ Discard | Cost$ B Sac<1/Creature> | ValidTgts$ Opponent | SorcerySpeed$ True | NumCards$ 1 | Mode$ RevealYouChoose | SpellDescription$ Target opponent reveals his or her hand. You choose a card from it. That player discards that card. Activate this ability only any time you could cast a sorcery.
 SVar:RemAIDeck:True
+SVar:NonStackingEffect:True
 SVar:Picture:http://www.wizards.com/global/images/magic/general/mind_slash.jpg
 Oracle:{B}, Sacrifice a creature: Target opponent reveals his or her hand. You choose a card from it. That player discards that card. Activate this ability only any time you could cast a sorcery.

forge-gui/res/cardsfolder/m/mirror_universe.txt

@@ -2,5 +2,6 @@ Name:Mirror Universe
 ManaCost:6
 Types:Artifact
 A:AB$ ExchangeLife | Cost$ T Sac<1/CARDNAME> | ValidTgts$ Opponent | TgtPrompt$ Select target opponent | ActivationPhases$ Upkeep | PlayerTurn$ True | SpellDescription$ Exchange life totals with target opponent. Activate this ability only during your upkeep.
+SVar:NonStackingEffect:True
 SVar:Picture:http://www.wizards.com/global/images/magic/general/mirror_universe.jpg
 Oracle:{T}, Sacrifice Mirror Universe: Exchange life totals with target opponent. Activate this ability only during your upkeep.

forge-gui/res/cardsfolder/m/moat.txt

@@ -2,7 +2,6 @@ Name:Moat
 ManaCost:2 W W
 Types:Enchantment
 S:Mode$ Continuous | Affected$ Creature.withoutFlying | AddHiddenKeyword$ CARDNAME can't attack. | Description$ Creatures without flying can't attack.
-SVar:NonStackingEffect:True
 SVar:RemRandomDeck:True
 SVar:Picture:http://www.wizards.com/global/images/magic/general/moat.jpg
 Oracle:Creatures without flying can't attack.