Setarasa: Mechanics

Remember: When you would draw a card, you may instead draw this card from exile. If you do, exile the top PARAM1 cards of your library from the game. Used on 2 cards: Flow of Insanity, Brand of the Mad

Potential U/R mechanic. Can probably see a splash in Black

Corrupted: Creatures you control without Corrupted have -1/-1 Used on 3 cards: Proof of Fright, Serena, the Primordial Fright, Priest of the Fright

The knowledge and presence of the old gods is a burden in itself. All color mechanic.

Enhance: As you cast a creature spell, you may reveal this card from your hand and pay its enhance cost. If you do, that creature gains all abilities of this card until end of turn. Used on 3 cards: Blood storm, Storm of Power, Shadow Reaper

Potential ability for B/R or R/G

Frenzy: Whenever this creature attacks and isn't blocked, it gets +PARAM1/+0 until end of turn. Used on 1 cards: Frenzied Berserker

Potential mechanic for B/R

Resistance: When this creature would die, if it isn't wounded, remove all damage from it and it becomes wounded. Used on 2 cards: Resilient Renegade, Dirk, Imperious Rebel

Other Potential B/R mechanic.

Rifting: When you draw this card, you may exile it. If you do, you may cast it for it's Rifting cost. At the end of turn, if it's still exiled, put it into your hand. Used on 4 cards: Rift Dragon, Rift Mage, Not Wipe Away, Not Wipe Away 2.0

Potential U/R mechanic

Discover: You gain a Discovery counter. Used on 3 cards: Pilgrim of the New, Strenght of the New, Apostle of the New World

Potential U/W mechanic

Rebirth: Whenever this creature dies, return from your graveyard to the battlefield at the beginning of your next upkeep. Used on 3 cards: Mausoleum Shambler, Gravespawn, Deepwood Shade

Pillage: Exile that card. You may cast it until end of turn. Used on 2 cards: Salvage Steel, Act on Impulse

Used as a card draw/steal for red.

Immortalize: PARAM1: CARDNAME becomes an enchantment. Used on 2 cards: Adept of the Dark, Immortal Sage

Possess: When this creature would die, you may pay PARAM1. If you do, this creature permanently becomes an Aura. Attach it to target creature. Used on 1 cards: Priest of Domination

Quicken: When this creature enters the battlefield, you may activate one of its abilities without paying its activation cost. Used on 1 cards: Aether Jumper

In card text or details pages, write the mechanic's code name (playtest name) between square brackets, like "[Crittercast]", "[Bushido 1]" or "[Delay 4 {2}{R}{R}]". It will be expanded to the mechanic's name plus reminder text, such as "Suspend 4 – {2} {r} {r} . (Rather than cast this spell from your hand,...)"
To expand a mechanic's name but not its reminder text, include parentheses at the end of the square brackets: "[Crittercast()]", "[Delay 9 {R}()]".