msem-instigator

Haste
Whenever this creature attacks, you may discard a card. If you do, draw a card.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
{3}{G}: Harmonic Recruit gets +2/+2 until end of turn. If you're in a renaissance, it gets +4/+4 until end of turn instead.

When Sorrowslayer enters, put a +1/+1 counter on target creature.
Remove a +1/+1 counter from Sorrowslayer: Trigger a death knell of a permanent you control. Activate only once each turn and only as a sorcery.

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.”)

Flying
When Mother of Owls dies, you may return target creature an opponent controls to its owner's hand.

Menace
Whenever you sacrifice an artifact or creature, Lava Scutterer deals 2 damage to any target.

Hexproof
At the beginning of each end step, if an opponent was dealt 4 or more damage this turn, return target instant or sorcery card from your graveyard to your hand.

Flying
Whenever Keeper of Twisted Light attacks, you gain 3 life.

At the beginning of your end step, judge target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

At the beginning of your upkeep, germinate. Then if creatures you control have total power 10 or greater, transform Mushroom Merchant. (To germinate, put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
At the beginning of your upkeep, put a +1/+1 counter on Fleshrender Demon and you lose 1 life.

Haste
When Caravan Engulfer enters, creatures you don't control can't block this turn.

{1}{G}: Marrow Gorger must be blocked this turn if able.

When Rat King enters, create two 1/1 black Rat creature tokens with “This creature can't block.”
Whenever Rat King or another creature you control dies, each opponent loses 1 life and you gain 1 life.

[+2]: Draw two cards, then discard two cards unless you discard an instant or sorcery card.
[–3]: Reveal any number of cards from your hand. Fulmen deals damage to any target equal to the number of instant and sorcery cards revealed.
[–9]: Search each player's library for up to one instant card and one sorcery card. Cast those cards without paying their mana costs. Then each player shuffles.

Artifact spells you cast cost {1} less to cast.
{2}, Sacrifice an artifact: Target creature gains deathtouch until end of turn.

Trample
When Oakcudgel Giant enters, you may destroy target artifact or enchantment.

[+1]: Scry 2. Create a 1/1 black Insect creature token with flying.
[–2]: Judge each creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)
[–8]: For each card type, search your library and graveyard for a card of that type and exile it, then shuffle. You may play any number of cards exiled this way without paying their mana costs.

Whenever a player activates an ability that isn't a mana ability, Burning-Tree Shaman deals 1 damage to that player.

Menace
When Azuma Hashiro, the Thronebreaker enters, you may cast up to two cards from your opponents' graveyards without paying their mana costs. If those spells would be put into a graveyard, exile that card instead.

Whenever another legendary creature you control enters, put a +1/+1 counter on The Lost and Seeking.
Surpass {4}{R}{W} ({4}{R}{W}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Return target creature to its owner's hand. Its controller loses 1 life.

Flash
Embellish {5}{U} (If you cast this spell for {5}{U}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
Whenever Vectis Entrancer or another artifact you control enters, tap target creature an opponent controls. It loses all abilities until end of turn.

{1}, Sacrifice Wayfarer's Amulet: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{3}, Sacrifice Wayfarer's Amulet: Search your library for a riddle card, reveal it, put it into your hand, then shuffle.

Return target creature card from your graveyard to your hand. Add {G}{G}{G}. Spend this mana only to cast creature spells.