msem-instigator

When Saddled Scuttleback enters, you may search your library for a Crab, Fish, Jellyfish, Kraken, Leviathan, Merfolk, Nautilus, Octopus, Otter, Oyster, Pirate, Seal, Serpent, Shark, Shrimp, Sponge, Squid, Starfish, Trilobite, Turtle, Whale, or Island card, reveal it, put it into your hand, then shuffle.

Once each turn, when you sacrifice a land, you may add one mana of any color. Until end of turn, you don't lose this mana as steps and phases end.

Target opponent sacrifices a creature.
Rerun (If you cast this from your hand, exile it as it resolves. Whenever a creature you control dies, you may cast this card from exile without paying its mana cost.)

Hellfire Caverns enters tapped.
{T}: Add {R}.
{2}{R}: Until end of turn, Hellfire Caverns becomes a 3/3 Devil creature with menace. Activate only if you're horrific.

Sacrifice Devoted Dancer: Target creature gains indestructible until end of turn. If it's your turn, shuffle Devoted Dancer into its owner's library.

When Twinforged Golem enters, create a 3/3 colorless Golem artifact creature token.

Deception {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Pay 1 life, Choose a creature card name you haven't chosen for Suzume Oshiruko this turn: Return another creature you control with the chosen name to its owner's hand.

Art of war — At the beginning of your end step, if Exultant Oni dealt damage to an opponent this turn, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

When Journey to Elrayin enters, journey, then choose a creature card name. (To journey, exile the top card of your library face up. Whenever a creature you control deals combat damage to a player, put a journeyed card you own into your hand.)
Whenever a creature you control with the chosen name deals combat damage to a player, journey.

Basic lands you control have all basic land types.
Augmented — Whenever you cast an instant or sorcery spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, copy it. You may choose new targets for the copy.

Target creature gets +2/+1 and gains haste until end of turn.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Kicker {X}{U} (You may pay an additional {X}{U} as you cast this spell.)
When Tidetwister Mage enters, if it was kicked, return all other creatures with power X or less to their owners' hands.

This spell costs {X} less to cast, where X is the number of creatures you control.
Vigilance

Bleed {1}{U/R} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Copy target instant or sorcery spell. You may choose new targets for the copy.

Reveal cards from the top of your library until you reveal a land card, then put that card onto the battlefield tapped. You may put another card revealed this way on top of your library. Put the rest of the cards revealed this way on the bottom in a random order.

Flying
When Slighted Spirit enters, detain up to two target creatures. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)

Target permanent gains indestructible and hexproof until end of turn. Remove all -1/-1 counters from it.

Improve {1} ({1}: 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.)
When Bridgehaven's Finest enters, create a 1/1 colorless Human creature token.
Other creatures you control get +1/+1 as long as Bridgehaven's Finest has two or more counters on it.

If an opponent would draw one or more cards, that player instead draws that many cards plus one, then exiles a card from their hand.
You may play cards exiled by Curated Citations, and you may spend mana as though it was mana of any type to cast them.

Put target creature card from a graveyard onto the battlefield under your control. If it doesn't have vanishing, put three time counters on it and it gains vanishing. (At the beginning of your upkeep, remove a time counter from that permanent. When the last is removed, sacrifice it.)

Whenever Ravaging Tyrant enters or attacks, each opponent loses 3 life, discards a card, and sacrifices a creature or planeswalker.

Rediscover an artifact card, then do the same for creature, enchantment, instant, land, planeswalker, and sorcery. (Each time, look at the top card of your library. You may reveal it and put it into your hand if it's of that type. Otherwise, put it back or into your graveyard.)

Danaj Temple enters tapped.
Satrapies you control have “{T}: Add {B} or {G}.”

Double strike, vigilance
At the beginning of combat on your turn, create X 1/1 red Dwarf creature tokens with haste, where X is the number of embattled nontoken creatures you control. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Search your library for two basic land cards, reveal them, put them into your hand, then shuffle.