msem-instigator

At the beginning of your second main phase, you may return a creature you control to its owner's hand. If you do, add {G}{U}.

Counter target nonenchantment spell.

Whenever Starfall Instructor attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Each opponent loses 2 life.

Destroy target creature. Then if there are ten or more cards in your graveyard, return target creature card from your graveyard to your hand.

Flash
Enchant instant or sorcery spell
Enchanted spell's text box is “This spell deals 3 damage to you.”
{4}{U}{U}{R}{R}: Return Mental Meltdown from your graveyard to the battlefield.

At the beginning of your upkeep, discard your hand.
{2}: Greater Masticore deals 1 damage to each other creature.
{6}, Exile six other cards from your graveyard: Return Greater Masticore from your graveyard to the battlefield tapped.

If a creature entering under you control causes an ability to trigger, you may pay -1. Whenever you do, copy that ability. You may choose new targets for the copy.
[+1]: Exile target creature. Return that card to the battlefield tapped under its owner's control at the beginning of the next end step. If you don't control it, it enters with a stun counter.
[–2]: Draw a card and gain 2 life.

First strike
Engage (This creature must be blocked each combat if able.)

Vanishing 2 (This permanent enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player discards one or more cards, put a time counter on Fleeting Moments.
Whenever a time counter is removed from Fleeting Moments, you draw a card and you lose 1 life.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Serul Cove Escort encourages a creature, that creature gains flying until end of turn.

This spell can't be countered.
Draw a card for each different mana value among nonland permanents you control.

Flying
Whenever Sinewed Wings deals combat damage to a player, you may discard your hand. If you do, draw a card for each creature with flying you control.

[+1]: Exile up to one target tapped creature.
[–2]: Create a 4/4 white Angel creature token with flying.
[–3]: Destroy all creatures. You gain 1 life for each creature destroyed this way.
[–7]: You get an emblem with “At the beginning of each end step, you gain life equal to twice the life you've lost this turn.”

Enchant creature
You may cast this spell from your graveyard if it targets a legendary creature you control.
Enchanted creature gets +2/+2 and has trample.

Indestructible (Damage and effects that say “destroy” don't destroy this creature.)

Flying
When this creature enters, target creature gains flying until end of turn.
Arise {3}{W}{W} ({3}{W}{W}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

As an additional cost to cast this spell, sacrifice a creature.
Create X Treasure tokens, where X is the sacrificed creature's mana value.

Vigilance
Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)

Eureka! (At the beginning of each end step, you get a research counter if you cast a spell this turn. Then if you have eight or more research counters, remove them and create a Masterpiece token of your choice.)
{T}: Draw a card, then discard a card.

The next time one or more creatures you control would die this turn, exile those cards. You may play them until the end of your next turn.

Flash
First strike (This creature deals combat damage before creatures without first strike.)

Haste
Whenever Herald of the Humble deals combat damage to a player, that player reveals the top card of their library. If it's a nonland card with mana value 3 or less, they may cast it without paying its mana cost.

Destroy target nonland permanent with mana value less than or equal to the number of cards in your graveyard.

When Ulvenwald Ranger enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
{1}{G}: Transform Ulvenwald Ranger. Activate only if it's attacking.

{1}{U}, Tap an untapped Noble you control: Hired Blades gets +2/+1 until end of turn and can't be blocked this turn.