msem-instigator

Whenever Wandering Conqueror attacks, it explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then you may put that card in your graveyard.)
As Wandering Conqueror explores a land, you may put that card into your graveyard. Whenever you do, Wandering Conqueror deals 2 damage to target player or planeswalker.

Rhapsody {5}{W}{W} (Pay {5}{W}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Whenever Oltenen Paradise-Seeker attacks, up to one target creature's base power and toughness each become equal to Oltenen Paradise-Seeker's power and toughness until end of turn.

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.
Mirage {W/U} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Cleansing Brimstone deals 2 damage to any target. If a creature or planeswalker dealt damage this way would die this turn, exile it instead.

Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)

Mill two cards, then you may return a permanent card that was put into your graveyard from anywhere this turn to your hand.

{T}: Add {C}.
{T}: Add {G}, {U}, or {R}. You can't spend this mana to cast a monocolored spell.

Whenever a card is put into a graveyard this turn, you may put it on the bottom of its owner's library.
Draw a card.

When Compulsion's Voice enters, gain control of target permanent until end of turn. Untap that permanent. It gains haste until end of turn.
Recite {1}{U}{R} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

I, II — Scry 2.
Discovery — Whenever a land you control enters, if it doesn't have the same name as another land you control, draw a card.

Whenever Imako, Ninefingers becomes tapped, exile the top three cards of target opponent's library face down.
You may look at cards exiled with Imako.
Sacrifice Imako: Turn all cards exiled with it face up. Exile all cards with those names from your opponent's graveyards.

Whenever you sacrifice a Clue, you lose life equal to the number of Clues you control, then investigate twice. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Flash
Deathtouch

Counter target spell unless its controller pays {2}.
Reprise {3}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

You may play an additional land this turn.
Draw a card.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Whenever a creature enters under an opponent's control, you may pay 2 life. If you do, draw a card.

[+1]: Search your library for a land card, put it onto the battlefield, untap it, then shuffle. Sacrifice a land.
[–2]: Destroy target noncreature permanent. Its controller may search their library for a basic land card, put that card onto the battlefield, then shuffle.
[–6]: Return any number of land cards from your graveyard to the battlefield and untap them. They become 3/3 creatures with haste in addition to their other types.

Menace, lifelink
Whenever a creature enters under an opponent's control, you may have that player lose 1 life.

{1}{G}: Marrow Gorger must be blocked this turn if able.

{T}: Untap target land.
{4}{G}: This creature gets +3/+3 until end of turn.

Until end of turn, creatures you control gain “When this creature dies, return a noncreature card from your graveyard to your hand.”

You have hexproof.
Creatures you don't control have base power and toughness 1/1 and lose all abilities.
Nonbasic lands you don't control don't untap during their controller's untap step.

{3}, {T}: Put a +1/+1 counter on target creature. This ability costs {3} less to activate if you've sacrificed a permanent this turn. Active only as a sorcery.

Vigilance (Attacking doesn't cause this creature to tap.)