msem-instigator

Flying, lifelink
Whenever Shioki, Imperial Heir attacks, exile any number of other target nonland permanents you control, then return those cards to the battlefield under their owner's control.

Equipped creature gets +2/+2 and has flying and lifelink.
When equipped creature deals combat damage to a player, unattach Shionoshio, Ocean's Vow, then transform it.
Equip {W}{U}
Shionoshio can be your commander.

Whenever Shoreline Stormers deals damage to a player, draw a card.
{2}{U}: Target creature can't be blocked this turn.

Vigilance
Whenever Sibling of All Elements attacks, it gains flying until end of turn if you control a creature with flying. The same is true for first strike, double strike, deathtouch, indestructible, lifelink, menace, and trample.

Prevent all combat damage that would be dealt to Silent Reaver.
Prevent all combat damage Silent Reaver would deal to creatures.

When Silver Gardener enters the battlefield, create a 1/1 green Saproling creature token.
Unveil {2}{G}{W} ({2}{G}{W}: Transform this. Unveil only as a sorcery.)

Whenever a creature dealt damage by Slave Child this turn dies, you may pay {B}. If you do, transform Slave Child.

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Slopestrider's Chariot's rider gets +1/+1 and has double strike.

Lifelink
When you attain Sojourner of the Beyond, create two 1/1 white Spirit creature tokens with flying. They gain haste until end of turn.

Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)
When Sower of Wishes enters the battlefield, reveal the top three cards of your library. Put all land cards revealed this way into your hand and the rest back on top in any order.

Creatures your opponents control can't block alone. (They can block different creatures.)

Each creature you control with power 4 or greater can't be blocked by creature tokens.

Sprout Hermit can't attack unless you control a creature with power 4 or greater.
Attain {3}{G} ({3}{G}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

If a card would be put into an opponent's graveyard from anywhere, instead that card is revealed and put on the bottom of that player's library.
Unveil {3}{G}{W} ({3}{G}{W}: Transform this. Unveil only as a sorcery.)

When you unveil Starlight Guardian, you may put target card from your graveyard on top of your library.
If a card would be put into an opponent's graveyard from anywhere, exile that card instead.

(Transform this if it's not attached to a creature. Pay {2}{U} as a sorcery to unattach it.)
Enchant creature you control
Steed of the Loch's rider gets +2/+1.
Whenever Steed of the Loch's rider attacks, you may tap target creature an opponent controls.

Stray Sighthound can't be blocked by creatures with power 2 or less.
Attain {3}{G} ({3}{G}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

[+1]: Each opponent loses 1 life for each card you've drawn this turn. Then you draw a card.
[–2]: Sun King's Shadow deals 2 damage to target creature or planeswalker and you gain 2 life. If that permanent was already dealt damage this turn, destroy it.

Reach
Whenever another creature enters, untap Sylvan Subversive.

Flying
Whenever a player taps a land for mana, return that land to its owner's hand unless they pay 1 life.
At the beginning of each end step, if an opponent controls no tapped lands, transform Tamaak, Drought of Life.

Double strike
At the beginning of each end step, if a creature you control died this turn, Tempered Survivor deals 2 damage to each opponent.

When you unveil Tempest Termagant, you may put target land on top of its owner's library.

Flash
When Tenvilu, Earthen Warden enters the battlefield, other creatures you control get +2/+2 and gain hexproof and indestructible until end of turn.

Flying, haste
Whenever The Branded Usurper attacks, it deals 2 damage to any target.
If you would lose the game, instead exile The Branded Usurper. Your life total becomes 0. Until an opponent's next turn, you can't lose the game and you can't gain life. Take an extra turn after this one.

Flying
Whenever a creature attacks you or a planeswalker you control, put a -1/-1 counter on that creature.