Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

Domineering Will

Target player gains control of up to three target nonattacking creatures until end of turn. Untap those creatures. They block this turn if able.

Aethersnatch

Gain control of target spell. You may choose new targets for it. (If that spell becomes a permanent, it enters under your control.)

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Mizzix of the Izmagnus

Whenever you cast an instant or sorcery spell with mana value greater than the number of experience counters you have, you get an experience counter.
Instant and sorcery spells you cast cost {1} less to cast for each experience counter you have.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Searing Touch

Buyback {4} (You may pay an additional {4} as you cast this spell. If you do, put this card into your hand as it resolves.)
Searing Touch deals 1 damage to any target.

Blatant Thievery

For each opponent, gain control of target permanent that player controls.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Ray of Command

Untap target creature an opponent controls and gain control of it until end of turn. That creature gains haste until end of turn. When you lose control of the creature, tap it.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Dominate

Gain control of target creature with mana value X or less.

Whispers of the Muse

Buyback {5} (You may pay an additional {5} as you cast this spell. If you do, put this card into your hand as it resolves.)
Draw a card.

Act of Aggression

({R/P} can be paid with either {R} or 2 life.)
Gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn.

Storm-Kiln Artist

This creature gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Insurrection

Untap all creatures and gain control of them until end of turn. They gain haste until end of turn.