Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

Force Void

Counter target spell unless its controller pays {1}.
Draw a card at the beginning of the next turn's upkeep.

Runeboggle

Counter target spell unless its controller pays {1}.
Draw a card.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Force Spike

Counter target spell unless its controller pays {1}.

Sol Ring

Daze

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
Counter target spell unless its controller pays {1}.