msem-instigator

Reach
Stonebark Incinerator gets +2/+0 and has trample as long as you control a Dwarf.
Stonebark Incinerator gets +0/+2 and has vigilance as long as you control a Elf.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Renown 3 (When this creature deals combat damage to a player, if it isn't renowned, put three +1/+1 counters on it and it becomes renowned.)

This spell can't be countered.
Flying
Dominance — Whenever Stormwing Ultrateryx becomes the target of a spell an opponent controls, if you control the creature with the greatest power or tied for the greatest power, counter that spell.

Exile up to one target artifact or enchantment.
Coalesce {5}{G} (You may cast this from your graveyard for {5}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever a creature you control becomes renowned, you may have it fight target creature you don't control. (Each deals damage equal to its power to the other.)

When Stygian Leviathan enters, target opponent loses life equal to the number of Curses attached to them and you gain that much life.

First strike, vigilance
When Subnautical Legionnaire enters, choose artifact, enchantment, or Merfolk. Exile target nonland permanent you don't control until you control no permanents of the chosen type.

When Sullen Bonecrusher enters, it deals damage to any target equal to the number of Warriors you control and you gain that much life.

When Sundering Arcanist enters, you may destroy target artifact or enchantment.
If you would draw a card, you may sacrifice a land and mill four cards instead. If you do, return Sundering Arcanist from your graveyard to your hand.

Whenever a land you control enters or a land card is put into your graveyard from anywhere, create a 0/1 green Plant creature token.
{3}{G}{G}: Put a +1/+1 counter on each other creature you control.

Flying
As long as it's your turn, creatures you control get +3/+0 and have vigilance.
As long as it's not your turn, creatures you control get +0/+3 and have lifelink.

Flash
Flying
When Sunset Herald enters, if it was cast, return to the battlefield all creature cards from your graveyard that were put there from the battlefield this turn.

Haste
At the beginning of your end step, return Sunwatcher Aspirant to its owner's hand.

Menagerie — When Supply Hauler enters, if there are five or more creature types among creatures you control, you may search your library for an artifact card, reveal it, put it into your hand, then shuffle.

When Swiftwheel Slayers enters, audition for red. (Create a 1/1 Construct Actor creature token, a Warrior Role giving 3/2 and trample, or a Wizard Role giving 2/2 and prowess. Roles replace older ones.)
Token creatures you control have haste.

Whenever a creature you control becomes blocked, you may return it to its owner's hand.
The first spell you cast during your postcombat main phase each turn costs {W}{U} less to cast. This effect reduces only the amount of colored mana you pay. (For example, if you cast a spell with mana cost {1}{U}, it costs {1} to cast.)

Flying
When T'nege, Skyguard enters, exile another target creature you control until T'nege leaves the battlefield. If you do, exile target creature an opponent controls until T'nege leaves the battlefield.

Menace
Whenever Tamaak's Mouth attacks, defending player sacrifices a nonland permanent.

Hexproof

Flying
When Tattered Wisp enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Flying
{2}{R}: Target creature attacks this turn if able.

Each player sacrifices a creature.
Coalesce {5}{B} (You may cast this from your graveyard for {5}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Flying
Whenever you aetherize, you may have Telarine Skychaser become an artifact creature until end of turn.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Defender

Tap up to one target nonbasic permanent. It doesn't untap during its controller's next untap step.
Coalesce {5}{U} (You may cast this from your graveyard for {5}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)