Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Time Spiral

Exile Time Spiral. Each player shuffles their hand and graveyard into their library, then draws seven cards. You untap up to six lands.

Mind Over Matter

Discard a card: You may tap or untap target artifact, creature, or land.

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Palinchron

Flying
When Palinchron enters, untap up to seven lands.
{2}{U}{U}: Return Palinchron to its owner's hand.

Mana Vortex

When you cast this spell, counter it unless you sacrifice a land.
At the beginning of each player's upkeep, that player sacrifices a land of their choice.
When there are no lands on the battlefield, sacrifice Mana Vortex.

Rhystic Study

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

Dream Halls

Rather than pay the mana cost for a spell, its controller may discard a card that shares a color with that spell.