Aetherize

Return all attacking creatures to their owner's hand.

Exocrine

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Bio-plasmic Barrage — When Exocrine enters, it deals X damage to each player and each other creature.

The Red Terror

Advanced Species — Whenever a red source you control deals damage to one or more permanents and/or players, put a +1/+1 counter on The Red Terror.

Mutalith Vortex Beast

Trample
Warp Vortex — When Mutalith Vortex Beast enters, flip a coin for each opponent you have. For each flip you win, draw a card. For each flip you lose, Mutalith Vortex Beast deals 3 damage to that player.

Magnus the Red

Flying
Unearthly Power — Instant and sorcery spells you cast cost {1} less to cast for each creature token you control.
Blade of Magnus — Whenever Magnus the Red deals combat damage to a player, create a 3/3 red Spawn creature token.

Exalted Flamer of Tzeentch

Sorcerous Inspiration — At the beginning of your upkeep, return an instant or sorcery card at random from your graveyard to your hand.
Fire of Tzeentch — Whenever you cast an instant or sorcery spell, Exalted Flamer of Tzeentch deals 1 damage to each opponent.

Vadrik, Astral Archmage

If it's neither day nor night, it becomes day as Vadrik, Astral Archmage enters.
Instant and sorcery spells you cast cost {X} less to cast, where X is Vadrik's power.
Whenever day becomes night or night becomes day, put a +1/+1 counter on Vadrik.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Chaos Mutation

Exile any number of target creatures controlled by different players. For each creature exiled this way, its controller reveals cards from the top of their library until they reveal a creature card, puts that card onto the battlefield, then puts the rest on the bottom of their library in a random order.