msem-instigator

Vigilance, trample
At the beginning of combat on your turn, put a +1/+1 counter on target legendary creature you control.

Flying, first strike, lifelink
When Stalwart Seraph enters, untap all creatures you control.

Take an extra turn after this one. At the beginning of that turn's upkeep, if you control a legendary creature, each opponent exiles the top card of their library. Until the end of that turn, you may play those cards and you may spend mana as though it were mana of any type to cast those spells.
Exile Stolen Moments.

This spell costs {2} less to cast if you control a legendary creature.
Search your library for a creature or land card, reveal it, put it into your hand, then shuffle.

Whenever you cast an instant or sorcery spell, you may attach Stormbreaker's Edge to target creature you control.
Equipped creature gets +3/+0.
Equip {3}

Flying
Stormcloud Drake gets +1/+0 for each instant and sorcery card in your graveyard.
Whenever Stormcloud Drake attacks, tap target creature defending player controls.

Target creature gains hexproof and indestructible until end of turn. If it's legendary, put a +1/+1 counter on it.

Improve {G} ({G}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever an Elf you control dies, you may search your library for a land card, reveal it, put it into your hand, then shuffle.

Exile target artifact or enchantment. If its mana value is 3 or less, draw a card.

Create two 2/2 white Griffin creature tokens with flying. If you control a legendary creature, create three of those tokens instead.

({T}: Add {W}.)
As Sunlit Meadow enters, you may pay 1 life. If you don't, Sunlit Meadow enters tapped.
Basic lands you control have “{T}: Add {W}.”

Whenever you create one or more creature tokens, you may pay {1}{G/W}. If you do, put a +1/+1 counter on Sylshal, Life's Gyre and on each creature token you control.

Vigilance
Whenever a legendary creature you control enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Whenever a creature you control becomes blocked, you may return it to its owner's hand.
The first spell you cast during your postcombat main phase each turn costs {W}{U} less to cast. This effect reduces only the amount of colored mana you pay. (For example, if you cast a spell with mana cost {1}{U}, it costs {1} to cast.)

Whenever you attack, you may draw a card. If you do, discard a card.

{G}, {T}: Create a 1/1 green Elf creature token.
{3}{G}{G}, {T}: Create a 3/3 green Beast creature token.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Whenever Tegan, the Sparrowhawk attacks, you may pay {R/W}. When you do, Tegan deals 1 damage to target creature if it's tapped. Otherwise, tap it.

{3}, {T}: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

This spell costs {3} less to cast if it targets a creature you control.
Exile target creature, then you may return it to the battlefield under its owner's control. Otherwise, put it on top of its owner's library.

This spell costs {1} less to cast for each artifact you control.
Gain control of target creature until end of turn. Untap that creature. It gains menace and haste until end of turn.

Creature tokens you control get +1/+1.
Whenever Thyra, Winter's Warden enters or attacks, you may pay {1}{G/W}. If you do, create Bruga, a legendary 2/2 green and white Wolf creature token.

Flash
Enchant creature
Enchanted creature gets +1/+1 and has first strike.

Towering Inferno deals X damage to each creature without flying. If a creature you don't control dealt damage this way would die this turn, exile it instead.

Tranquil Shrine enters tapped.
When Tranquil Shrine enters, if you don't control a legendary creature, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.