msem-instigator

(Activate each submodule once as a sorcery. When this enters, activate one submodule for free.)
{U}{U}{U}: Premise
Create a token that's a copy of target creature.
{U}{U}{U}: Inference
Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.
{U}{U}{U}: Conclusion
Logic Module gains “Whenever a creature you control deals combat damage to an opponent, you may draw a card.”

Flying
Long-Finned Skywhale can block only creatures with flying.

Take an extra turn after this one. Exile Look to the Future.
Civilized — If you control an artifact, a creature, and an enchantment, until the end of your next turn, you may look at the top card of your library any time and you may play the top card of your library.

Flying
When Lord Rokai becomes the target of a spell, sacrifice it.
Whenever you cast an instant or sorcery spell, you may pay {2}{U}. If you do, return Lord Rokai from your graveyard to the battlefield.

Prowess
Whenever you cast a noncreature spell, noncreature spells you cast cost {1} less to cast until end of turn.

Other Merfolk you control get +1/+1.
{1}{U}: Target Merfolk gains slipstream until end of turn. (Creatures with slipstream can't be blocked as long as only creatures with slipstream are attacking.)

Instant, sorcery, and legendary spells you cast cost {1} less to cast.

Return target nonland permanent to its owner's hand.
Dominance — If you control the creature with the greatest power or tied for the greatest power, you may put that permanent on top of its owner's library instead.

Submerge target spell. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Counter target spell. Create a 1/1 blue Elemental creature token with flying.

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

Counter target spell, activated ability, or triggered ability. Its controller chooses draw step, main phase, or combat phase. That player skips each instance of the chosen step or phase during their next turn. (Mana abilities can't be targeted.)

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Put target creature [spell] on top of its owner's library.

Lost Station enters tapped.
{T}: Add {U}.
{U}{U}: Until end of turn, Lost Station becomes a 2/2 Horror creature with “This creature can't be blocked.” Activate only if you're horrific.

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.”

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.

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.

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

Reveal the top card of your library. Draw X cards, where X is that card's mana value.

Lumbering Stoneshell has hexproof as long as it's untapped.

This spell can't be countered.
Trample
Whenever Lumbering Thoctar becomes the target of a spell or ability, counter it. Then put a stun counter on Lumbering Thoctar.
Whenever Lumbering Thoctar becomes untapped, draw a card.

{T}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
At the beginning of combat on your turn, you may exile a creature card from your graveyard. When you do, target creature with the same power as the exiled card can't be blocked this turn.

Flying
Crew 2
Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
As long as you're in a renaissance, Lunar Shachuan is an artifact creature.

Look at the top three cards of target player's library. Put one back and exile the rest.
Coalesce {5}{U} (You may cast this from your graveyard for {5}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Whenever Lurk at Vision's Edge attacks, defending player exiles the top five cards of their library.