msem-instigator

When Gamhaugen Stablehand enters, put a +1/+1 counter on target creature you control. You gain 1 life.

As long as you control five or more creatures, if you would create a token, you may instead create Hu Li, a legendary 4/4 white Fox Spirit creature token with flying and lifelink.

Enchant creature
Enchanted creature gets -1/-1 and can't block.
Enchanted creature gets an additional -1/-1 for each card named Garrote in your graveyard.

Whenever you cast a noncreature spell, put a quest counter on Gate to the Beyond.
At the beginning of your upkeep, if there are three or more quest counters on Gate to the Beyond, you draw a card and you lose 1 life. Then if there are six or more quest counters on it, each opponent loses 2 life.

Enchant opponent
Enchanted player plays with the top card of their library revealed.
Whenever enchanted player casts a spell, you may have them mill a card.

Choose flying, prowess, vigilance, or ward {2}. Create a colorless Equipment artifact token with “Equipped creature has the chosen ability” and equip {2}. (Then exile this card. You may cast the creature later from exile.)

Whenever Gentry Infiltrator deals combat damage to a player, you may search that player's library for a creature card and exile it. If you do, that player shuffles.
{2}{U}{U}: Gentry Infiltrator becomes a copy of a creature card exiled with it until end of turn.

Until end of turn, target creature you control gains “When this creature dies, return it to the battlefield under your control with a +1/+1 counter on it.”

Target creature gets +3/+3 until end of turn.

Until end of turn, target creature you control gains “{T}: This creature deals 1 damage to any target.”
Draw a card.

Regenerate target creature. (The next time that creature would be destroyed this turn, it isn't. Instead tap it.)

As an additional cost to cast this spell, discard a card.
Draw two cards. Gift of the Phoenix deals 2 damage to you.

Prevent all damage that would be dealt to each of up to three target permanents this turn.

Prowess
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Draw two cards. [Then discard two cards.]

Look at the top five cards of your library. You may reveal an enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
{3}{G}: Gloomhollow Woodlurker must be blocked this turn if able.

Exile target creature you control, then return it to the battlefield under its owner's control.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

You get a glory counter, then gain life equal to the number of glory counters you have. (You lose glory counters before life. A player with ten or more glory counters wins the game.)
Draw a card.

When Glowspore Grove enters or leaves the battlefield, create a 1/1 blue Elemental creature token with flying.

Whenever you cycle a card, reveal the top two cards of your library. You may put a permanent card from among them into your hand. Put the rest on top of your library in any order or into your graveyard.
Cycling {2} ({2}, Discard this card: Draw a card.)

Enchant player
At the beginning of enchanted player's end step, if they cast a spell this turn, they lose 1 life.

When Goblin Arsonist dies, you may have it deal 1 damage to any target.

Haste
Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)

When Goblin Rocktosser enters, you may sacrifice a land. If you do, put a +1/+1 counter on Goblin Rocktosser.