msem-instigator

Whenever you attack, you gain 1 life for each attacking creature.
{5}{W}: Put a -1/-1 counter on target tapped creature. This ability costs {X} less to activate, where X is the amount of life you gained this turn.

Return target creature to its owner's hand.
Coalesce {4}{U}{U} (You may cast this from your graveyard for {4}{U}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

When Vale Ruins enters, you gain 1 life.
{T}, Sacrifice Vale Ruins: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Whenever an opponent casts a spell during your turn, create a token that's a copy of Resurging Rhino.

{7}{U}: Tap up to three target nonland permanents. This ability costs {2} less to activate if you control a legendary creature.

Fahrib's Tongue can't be blocked by creatures with two or more creature types.
Whenever Fahrib's Tongue deals combat damage to a player, that player loses 1 life for each creature that dealt damage to them this turn.

Harmony — You may pay {1}{G}. If you do, create a 3/3 green Beast creature token.
When Wildheart Chorister enters, harmonize. (Trigger up to one harmony of a permanent you control.)

Whenever Tremor Titan enters or attacks, each player sacrifices a permanent. Then you draw a card for each opponent who sacrificed a land this way.

When Feathered Dancer enters, up to three target creatures can't block this turn.

Lifelink
Whenever a planeswalker dies, Onya's Chosen deals 3 damage to target creature or player.

Flying
Whenever you cast your first spell each turn, add {U}{U}, {U}{R}, or {R}{R}.
Whenever you cast your second spell each turn, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Whenever you cast your third spell each turn, Stirring Igmel deals 3 damage to each opponent.

Your opponents can't cast spells or activate abilities that aren't mana abilities this turn.

{T}: Add {C}.
{T}, Sacrifice Shiftscape Morass: Choose a basic land type other than Swamp. Create a colorless land token that's a Swamp and the chosen basic land type. Activate only during your upkeep.

Flash
When Guppyfin Duelist enters, create a green Aura enchantment token named Piranha's Prowess attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2.” Untap that creature.

Enchant creature
Enchanted creature is a blue Frog with base power and toughness 1/1 and loses all other card types, creature types and abilities.

Create a 5/5 green Badger Bear creature token with trample. (Then exile this card. You may cast the creature later from exile.)

Whenever an artifact or enchantment you control enters, Armament Scavenger gets +1/+0 and gains trample until end of turn.

When Enlightened Orator enters, choose one —
• Other creatures you control get +1/+1 until end of turn.
• Destroy target enchantment.

Whenever Solemn Stag perseveres, put two +1/+1 counters on it. (A creature perseveres when it survives damage.)

Mill five cards, then for each of those cards, a creature you control salvages that card unless an opponent pays 3 life. (Exile it from your graveyard until that creature leaves the battlefield. Whenever that creature deals combat damage to a player, put a card it salvaged into your hand.)

Artifacts and lands enter tapped.

Flying

Reach
When Creep of the Crop dies, mill three cards, then you may return a land card from your graveyard to your hand.
Foreshadow {1}{G} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

At the beginning of your upkeep, mill a card.
{B}, Sacrifice Cruel Consultation: Exile any number of cards from your graveyard. Create an X/X black Djinn Horror creature token, where X is the number of card types among cards exiled this way.