msem-instigator

If a card would be put into an opponent's graveyard from anywhere, instead that card is revealed and put on the bottom of that player's library.
Unveil {3}{G}{W} ({3}{G}{W}: Transform this. Unveil only as a sorcery.)

{3}{W}{W}: Put a divinity counter on Paragon of Noon. It gains indestructible.
Whenever Paragon of Noon attacks, if it has a divinity counter on it, search your library for a creature card with mana value 1, put it onto the battlefield tapped and attacking, then shuffle.

Lantern-Bearer Belle gets +2/+0 and has flying as long as you've sacrificed a permanent this turn.

{4}{G}, Discard a card: Reveal cards from the top of your library until you reveal a nonland permanent card. Put that card onto the battlefield and the rest into your graveyard.

You gain 2 life. Then if you have more life than an opponent, draw a card.
At the beginning of your upkeep, if Bittersweet Reunion is in your graveyard, you may pay {1}{W} and exile it. If you do, you may copy it and cast the copy without paying its mana cost.

When Defiant Bristles dies, put a +1/+1 counter on target creature.

Overgrown Siren must be blocked if able.

{1}{U}: Return Sparkling Jackalope and target creature to their owner's hands.
{5}{U}{U}: Sparkling Jackalope gets +4/+4 and gains flying until end of turn.

Anomalion enters with a +1/+1 counter on it.
{1}{G}{W}: Permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

Destroy target artifact or land.

You may have Mirror Mirage enter as a copy of any land on the battlefield, except it's an enchantment in addition to its other types.

(As an Encounter enters, choose an opponent to protect it. You and others can attack it. When defense counters are removed, create a 0/0 Army token if you don't control one, then put that many +1/+1 counters on a Army you control.)
When Settling of Kaneh enters, create two 1/1 white Soldier creature tokens if you control fewer creatures than an opponent. Then you gain 4 life if you have less life than an opponent.

Reach
Scarecrow spells you cast cost {1} less to cast.

{T}, Tap an untapped creature you control: Choose one —
• Add one mana of any color.
• Target player loses 2 life.
• Target player gains 3 life.
• Target player mills four cards.

Flash
Whenever Thundermane Fox enters or attacks, target creature you control gains double strike until end of turn.

{T}: Add one mana of any color.
{4}, {T}, Sacrifice Ancestral Tapestry: Search your library for a legendary card, reveal it, put it into your hand, then shuffle.

{T}: Add {C}.

[+1]: Create a 1/1 white Cat creature token with lifelink.
[–1]: When you next activate a nonmana ability of target permanent this turn, copy that ability. You may choose new targets for the copy.
[–7]: Exile up to seven target permanents. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Overgrown Enclave enters tapped.
{T}: Add {G} or {U}.
{4}{G}{U}: Until end of turn, Overgrown Enclave becomes a Turtle creature with ward {2} in addition to its other types.
Scavenge {5}{G}{U}

Target creature you control gets +2/+2 until end of turn. If it's attacking, it gains indestructible until end of turn.

When Ankulith Shard enters, draw a card.
{1}, {T}: Add one mana of any color.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
If a spell or ability would target you, it targets each player instead.
Whenever an opponent attacks you with one or more creatures, tap all noncreature permanents that player controls.

Draw two cards.
Rerun (If you cast this from your hand, exile it as it resolves. Whenever a creature you control dies, you may cast this card from exile without paying its mana cost.)

[+1]: Tap up to one target nonland permanent. It doesn't untap during its controller's next untap step, and its activated abilities can't be activated until it becomes untapped.
[–4]: Target player skips their next untap step.
[–8]: Exile all tapped permanents.

Creature spells you cast cost {2} less to cast.
Whenever another nontoken creature you control enters, it becomes a colorless Vehicle artifact with crew 1. (Tap any number of creatures you control with total power 1 or greater: That Vehicle becomes an artifact creature until end of turn.)