msem-instigator

When Serene Initiate enters, rouse 1. (Put a +1/+1 counter on a permanent you control. If it isn't a creature, tap it and it becomes a 0/0 creature in addition to its other types.)
{3}{G}{G}: Creatures you control get +2/+2 and gain trample until end of turn.

Haste
Ward—Sacrifice a creature.
Spinning Gears Abomination enters with X +1/+1 counters on it.
Spinning Gears Abomination can't attack alone.

Flash
Enchant creature
Enchanted creature gets -2/-2 and can't block creatures you control.

Discard your hand, then draw seven cards. When you do, you may cast a card with mana value X or less from your hand without paying its mana cost, where X is the number of card types among cards in your graveyard.

Lifelink
If a source would deal damage to a player, you may prevent X of that damage, where X is the number of +1/+1 counters on Mending Caretaker.

Enchant creature
Enchanted creature gets +2/+0 and has haste.

{3}{G}: Elder Rootwallas gets +4/+2 until end of turn. Activate only once each turn.

Enchant creature
Enchanted creature gets -6/-0.
Mirage {1}{U} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Lifelink
Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom in a random order.)
Mirage {2}{W}{W} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Flying
Death knell — Put a flying counter on target creature you control. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Whenever a -1/-1 counter is put on a creature, you may create a 1/2 green Frog creature token.

When Irrigation Trawler enters, reveal the top card of your library. If that card was a land card, put that card into your hand. Otherwise, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

You may put a creature card from your hand onto the battlefield. That creature gains haste until end of turn. Sacrifice that creature at the beginning of the next end step unless you pay its mana cost reduced by up to {3}{R}{R}.

Foretell {2}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Attacking creatures get +2/+0 until end of turn. If this spell was foretold, those creatures also gain trample until end of turn.

This spell costs {3} less to cast if a creature died this turn.
Hatefire deals 6 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

[+1]: Discard a card. If you did, draw a card.
[–2]: Create a Bullet token. Until end of turn, if a Bullet you control would deal damage, it deals that much damage plus 1 instead. (It’s an artifact with “{T}, Sacrifice this artifact: It deals 1 damage to any target.”)

{2}{R/G}: Wildershrine Warden gets +2/+2 until end of turn. You may have it assign its combat damage this turn as though it weren't blocked. Activate only once each turn.

Flying, lifelink
Legendary creatures you control get +1/+1.

You may cast up to two target instant and/or sorcery cards from your graveyard this turn. If a spell cast this way would be put into your graveyard, exile it instead.

Fury Swipes deals 2 damage divided as you choose among one or two targets. Scry 2.

Menace (This creature can't be blocked except by two or more creatures.)
Assault {R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)

Primal {1}{B} (During your turn, you may cast this spell for {1}{B} instead of playing a land.)
Each opponent discards two cards.

Whenever another creature you control enters, Loisch deals 1 damage to any target.
{4}{R}{G}: Loisch gets +X/+X and gains trample until end of turn, where X is the number of creatures you control.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create two 1/1 colorless Construct Actor creature tokens.
II — Creatures you control gain first strike until end of turn.
III — Creatures you control get +1/+0 until end of turn.

Flash
Deathtouch, lifelink
Whenever Irika, Wielder of Secrets deals combat damage to a player, you may pay {U/B}. If you do, you draw a card and you lose 1 life.