msem-instigator

Whenever you cast an instant or sorcery spell, you may exile that card instead of putting it anywhere else as it resolves.
At the beginning of your upkeep, Clash Reactor deals X damage to each opponent, where X is the number of colors of cards exiled with Clash Reactor.

Target creature fights another target creature. (Each deals damage equal to its power to the other.)

Flying
Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

Enchant creature
When Claustrophobia enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Whenever a creature enters under an opponent's control, you may have that player lose 1 life.
Unveil {2}{B}{R} ({2}{B}{R}: Transform this. Unveil only as a sorcery.)

When Clawing Shaman enters from your graveyard, you may exile it. If you do, return all creature cards from your graveyard to the battlefield.
{4}{B}{B}{B}, Sacrifice a creature: Return Clawing Shaman from your graveyard to the battlefield. Activate only as a sorcery.

This spell costs {1} less to cast for each card you've discarded this turn.
Draw three cards.

Sacrifice a creature: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

This spell costs {1} less to cast for each creature you attacked with this turn. (Those creatures don't have to still be on the battlefield.)
Flying

{W}, {T}: Tap target creature.

Return target nonland permanent to its owner's hand.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Target creature you control gets +1/+1 until end of turn. It deals damage equal to its power to target creature you don't control.

Exile target nonland permanent.

Search your library for up to two basic land cards, reveal those cards, and put one onto the battlefield tapped and the other into your hand, then shuffle.
Coalesce {7}{G} (You may cast this from your graveyard for {7}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Cleave deals 1 damage to each opponent and 1 damage to each creature and planeswalker your opponents control.

Soldiers you control get +1/+1.
Whenever one or more creatures attack, create a 1/1 red Soldier creature token.

Return target creature you control and target creature you don't control to their owners' hands.

Whenever you cast an instant or sorcery spell, Clever Infiltrator gets +2/+0 until end of turn and can't be blocked this turn.

Cast this spell only during your turn.
Draw a card. Then if an opponent cast a spell this turn, scry 1 and draw an additional card.

Choose target creature you control. Double its power and toughness until end of turn. That creature deals X damage divided as you choose among any number of target creatures and/or planeswalkers your opponents control, where X is its power.

Equipped creature has flying.
Equip {3}

When Climber's Outfit enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Equipped creature has reach.
Equip {1}

When Climbing the Oldest Mountain enters, draw a card, then choose a card name.
Whenever a creature you control with the chosen name deals combat damage to a player, put two +1/+1 counters on it.

Create a 2/2 black Zombie creature token.
Tether (Then if you cast this from your hand, you may exile it tethered to a creature you control. When it dies, you may cast this from exile without paying its mana cost.)