Sen Triplets

At the beginning of your upkeep, choose target opponent. This turn, that player can't cast spells or activate abilities and plays with their hand revealed. You may play lands and cast spells from that player's hand this turn.

Paradox Haze

Enchant player
At the beginning of enchanted player's first upkeep each turn, that player gets an additional upkeep step after this step.

Utter End

Xanathar, Guild Kingpin

At the beginning of your upkeep, choose target opponent. Until end of turn, that player can't cast spells, you may look at the top card of their library any time, you may play the top card of their library, and you may spend mana as though it were mana of any color to cast spells this way.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Counterspell

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Sol Ring

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.")

Azorius Signet

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Negate

Control Magic

Enchant creature
You control enchanted creature.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Gilded Lotus

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.