msem-instigator

Whenever Overgrowth Host attacks, germinate. Then creatures you control that are Saprolings or have counters on them gain trample until end of turn.
Saprolings you control get +1/+1.

At the beginning of your end step, you may pay {W}. If you do, exile target creature you control, then return that card to the battlefield under your control.

Whenever a creature you control deals combat damage to a player, it cackles. (Put a menace counter on it. If it already has menace, it deals 1 damage to each opponent instead.)
{3}{B}: Each creature you control with menace gains lifelink until end of turn.

Whenever Quick-Witted Slayer deals combat damage to a player, you draw a card and you lose 1 life.

{1}{U}: Target creature can't be blocked this turn.

[+1]: Mpumo, Who Stands Alone deals 1 damage to any target and you gain 1 life.
[–X]: Exile target creature with mana value X.
[–6]: Choose up to four permanents an opponent controls. That player chooses one, then sacrifices the rest.

Target creature you control deals damage equal to its power to target creature you don't control. Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

All creatures able to block Osheen Courtier do so.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Each opponent sacrifices a creature or planeswalker.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Young Tempter enters, you draw a card and you lose 1 life.

Choose one —
• Target permanent gains protection from instants and sorceries until end of turn.
• You gain 3 life.
• Draw a card.

Menace
Vanguard — Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each creature card in your graveyard.

When Drownyard Scavenger enters, each player may return an instant or sorcery card from their graveyard to their hand.

Flash
Flying
Whenever you cast a spell during an opponent's turn, create a Weapon token. When you do, you may attach it to another target creature with flying. (It's an Equipment artifact token with equip {2} and “Equipped creature gets +1/+1”.)

Trample, hexproof
Renown 4 (When this creature deals combat damage to a player, if it isn't renowned, put four +1/+1 counters on it and it becomes renowned.)
{1}{G}: Target creature blocks Tsolmon, the Huntress this turn if able.

Enchant creature you control
When Brawnsurge enters, enchanted creature deals damage equal to its power to up to one target creature an opponent controls.
Enchanted creature gets +1/+1 and has trample.

Return up to two target creatures to their owners' hands.

Deathtouch
When Shadowed Apostle dies, draw a card.

Return up to one target creature card from your graveyard to the battlefield tapped. You gain 2 life.
Tether (Then if you cast this from your hand, you may exile it tethered to a creature you control. When it dies, you may cast this from exile without paying its mana cost.)

{T}: Add {C}.
{6}, {T}, Discard a card: Search your library for a multicolored card, exile it, then shuffle. If its mana value is 3 or less, you may cast it without paying its mana cost. If you don't, put it into your hand. Activate only as a sorcery.

Search your library for up to four basic land cards with different names, reveal them, put them into your hand, then shuffle.

Destroy target creature. Its controller discards a card.

Whenever you cast an instant or sorcery spell, Infernal Immolator deals 2 damage to each opponent.

{T}: Add {C}.
Concord — {T}: Create a Treasure token. Activate only if there are four or more card types among permanents you control.

Deploy 2 (As this enters, you may tap any number of other creatures you control with total power 2 or more.)
When Rogue Groundskeeper enters deployed, exile up to two target cards from a single graveyard.