msem-instigator

Target creature gets +1/+0 and gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

When Scribal Puppeteer enters, create two 1/1 black Puppet creature tokens with “At the beginning of your upkeep, you lose 1 life.”

When Trapped in the Tower enters, exile target creature an opponent controls until Trapped in the Tower leaves the battlefield. (That creature returns under its owner's control.)
When you lose life, sacrifice Trapped in the Tower.

Deathtouch
When Nyx-Eater Basilisk enters, exile up to one target enchantment.
{2}{G}, Discard Nyx-Eater Basilisk: Exile target enchantment.

Whenever you draw a card, choose one —
• Dayang's Artistry deals 1 damage to any target.
• You gain 1 life.
• Scry 1.

Flash
When Charnel Legion enters, destroy target creature or planeswalker an opponent controls that was dealt damage this turn. When you do, you gain 2 life.

Exile target creature you control and each creature blocking or blocked by it.

Archive 4 (As this enters, shuffle the top four cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
At the beginning of each opponent's upkeep, that player may pay 2 life. If they do, you gain 2 life. Otherwise, you draw a card from the archived library.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
{2}, Sacrifice a creature: Put a +1/+1 counter on Desert Marauder.

Target creature you control gets +2/+0 and gains indestructible until end of turn. You lose 2 life.

Whenever Hero of Aer attacks, it gets +2/+1 until end of turn.

Create X 1/1 blue Boar Dragon creature tokens with flying. (Then exile this card. You may cast the creature later from exile.)

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

({T}: Add {R} or {W}.)
Jagged Crag enters tapped.

At the beginning of combat on your turn, create a 1/1 colorless Servo artifact creature token. It gains haste and attacks this turn if able.
Whenever a creature you control dies, you may pay {1}. If you do, put a +1/+1 counter on target creature.

Choose target creature. Scry 3, then reveal the top card of your library. You gain X life and put X +1/+1 counters on that creature, where X is the revealed card's mana value.

Whenever a creature you control with power 4 or greater deals combat damage to a player, you may draw a card.

{T}: Add {C}.
{T}, Pay 1 life: Add {U}.
{4}{U}, {T}, Sacrifice Verdant Oasis: Draw two cards. Activate only as a sorcery.

{8}{U}{U}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)
When Shipway Whale becomes monstrous, target player exiles all cards in their library, then shuffles their graveyard into their library.

Up to two target creatures can't be blocked this turn. Until end of turn, whenever either of those creatures deals combat damage to a player or planeswalker, you draw a card.

Choose two —
• Return up to two target creature cards from your graveyard to your hand.
• Return up to two target enchantment cards from your graveyard to your hand.
• Return up to two target artifact cards from your graveyard to your hand.
• Target player may put a permanent card from their hand onto the battlefield.

First strike, menace, lifelink
{X}{2}{B}, Discard Wihtfyr: Create a tapped 0/0 Skeleton Army creature token with “This creature gets +1/+1 for each creature card in your graveyard.” For each of up to X Armies, put your choice of a first strike, lifelink, or menace counter on that Army.

When Sandwurm's Might enters, you may have target creature you control fight target creature you don't control.
Each creature you control enters with an additional +1/+1 counter on it.

Flying, haste
Whenever Epoch Warden attacks, you may aetherize another target attacking creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

Blazing Offerings deals 4 damage to target creature or planeswalker.