Rhystic Shield

Creatures you control get +0/+1 until end of turn. They get an additional +0/+2 until end of turn unless any player pays {2}.

Rhystic Tutor

Unless any player pays {2}, search your library for a card, put that card into your hand, then shuffle.

Erosion

Enchant land
At the beginning of the upkeep of enchanted land's controller, destroy that land unless that player pays {1} or 1 life.

Rhystic Scrying

Draw three cards. Then if any player pays {2}, discard three cards.

Rhystic Circle

{1}: Any player may pay {1}. If no one does, the next time a source of your choice would deal damage to you this turn, prevent that damage.

Rhystic Lightning

Rhystic Lightning deals 4 damage to any target unless that permanent's controller or that player pays {2}. If they do, Rhystic Lightning deals 2 damage to the permanent or player.

Rhystic Deluge

{U}: Tap target creature unless its controller pays {1}.

Rhystic Syphon

Unless target player pays {3}, that player loses 5 life and you gain 5 life.

Rhystic Cave

{T}: Choose a color. Add one mana of that color unless any player pays {1}. Activate only as an instant.

Esper Sentinel

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

In the Eye of Chaos

Whenever a player casts an instant spell, counter it unless that player pays {X}, where X is its mana value.

Rhystic Study

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