msem-instigator

When Lost Crew enters or dies, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)
{1}{B}: Lost Dancer becomes black and gains lifelink until end of turn.

Lost Explorer has first strike as long as it's attacking.
{1}{B}, Exile Lost Explorer from your graveyard: Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

When Lost Kitten leaves the battlefield, create a 1/1 white Peasant creature token.

Enchant opponent
When Lost Knowledge enters, enchanted player reveals their hand.
{1}, Sacrifice Lost Knowledge: Scry 2, then draw a card.

Choose two —
• You gain 3 life.
• Lost Memories deals 3 damage to any target.
• Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Counter target spell. If a noncreature spell is countered this way, conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Target player discards two cards.

Exile target nonland permanent.

Put target nonland permanent on top of its owner's library.
Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Target creature gets +2/+2 until end of turn. Untap it.

Look at the top three cards of your library. Put one of them into your hand. Put Lost in Deep Storage and the rest on the bottom of your library in any order.

Exile target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

This spell costs {1} less to cast if you've cast another spell this turn.
Destroy target creature.

Enchant creature
When Lost to the Elements enters, if enchanted creature isn't in a pack, tap it. (Two or more creatures with the same controller and equal power are in a pack.)
Enchanted creature doesn't untap during its controller's untap step.

Lifelink
{B}, Sacrifice Lostrite Evoker: Add {B}{B}{B}.

When Lotus Feaster enters, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Add three mana of any one color.

When Lotus Wastes Survivalist enters, target player discards a card. Create a Treasure token unless a nonland card was discarded this way.

Creatures you control gain lifelink until end of turn.

Trample
Lotusleaf Blade gets +1/+1 as long as you control another Warrior.

Up to two target creature can't block this turn.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Vigilance
Whenever Lowly Cataphract and at least two other creatures attack, put a +1/+1 counter on Lowly Cataphract.
Surpass {5}{W} ({5}{W}: Transform this. This costs {1} less to activate for each counter on
it. Activate only as a sorcery.)

Whenever an Equipment you control enters, attach it to target creature you control.

Create a 1/1 white Bird creature token with flying. (Then exile this card. You may cast the creature later from exile.)