Ivory Tower

At the beginning of your upkeep, you gain X life, where X is the number of cards in your hand minus 4.

Spell Blast

Counter target spell with mana value X. (For example, if that spell's mana cost is {3}{U}{U}, X is 5.)

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Air Elemental

Counterspell

Unsummon

Return target creature to its owner's hand.

Island

Braingeyser

Control Magic

Enchant creature
You control enchanted creature.