msem-instigator

[+2]: Exile another target permanent, then return it to the battlefield under its owner's control.
[–2]: Gain control of target creature unless its controller pays its mana cost.
[–5]: You get an emblem with “If a nonland permanent would enter and it wasn't cast, it you control enters instead.”

Flash
When Kaivilu, Ocean Warden enters, creatures your opponents control get -2/-2 and lose all abilities until end of turn.

Enchant creature
When Kalku Initiation enters, you lose 3 life and discard a card.
Enchanted creature gets +3/+2, has ward {2}, and has “Whenever this creature deals damage to a player, draw two cards.”

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Sacrifice a land: Put a card from the archived library into your hand.

[+2]: Look at the top card of your library. If it's a permanent card with mana value less than the number of lands you control, you may put it onto the battlefield.
[–1]: Sacrifice a land. If you do, draw three cards.
[–7]: Destroy up to X target permanents, where X is the number of lands you control.

Kuyen, Moon Spirit can't attack or block unless there are ten or more cards in your graveyard.
At the beginning of each opponent's end step, create two Food tokens. Then you may pay 3 life. If you do, surveil 3, then draw two cards.
When Kuyen dies or is put into exile from the battlefield, you may put her into her owner's library third from the top.

Legacy (You may play this side of this card only from your graveyard. Exile it if it would be put into a graveyard or not resolve.)
Target creature gets -4/-4 until end of turn. When that creature dies this turn, other creatures its controller controls get -1/-1 until end of turn.

Whenever an opponent attacks, exile Last Offer. If you do, target opponent sacrifices an attacking creature and you return another enchantment card from your graveyard to your hand.

Exile the top seven cards of your library. Choose up to one card of each card type and put those cards into your hand.

Legacy (You may play this side of this card only from your graveyard. Exile it if it would leave the battlefield or not resolve.)
At the beginning of your end step, you may search your library for a creature card, reveal it, put it into your hand, then shuffle.

Whenever you activate a loyalty ability of a planeswalker, you gain 1 life.

Hexproof from spells cast from a graveyard
If a creature you control would die and that creature was the target of an instant or sorcery spell this turn, you may put it on top of its owner's library instead.

{T}: Add {C}.
At the beginning of your end step, if you control three or more enchantments, you may pay {W}. If you do, create a 0/1 white Llama creature token.

{T}: Add {C}.
{3}{W}: Until end of turn, Llereaux's Lair becomes a 1/2 creature. It's still a land. It can't be blocked this turn if {U} was spent to activate this ability, has indestructible if {B} was spent, and gets +2/+1 if {R} was spent.

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
If you would draw a card from an archived library, draw a card from each of your archived libraries instead. (Archived libraries are those that still have their Study in play.)

[+2]: Up to one target creature gets +3/+1 until your next turn. Up to one target creature gets -3/-1 until your next turn.
[–2]: Up to two other target permanents you control become a copy of another target permanent until your next turn.
[–8]: Exchange your library and hand, then shuffle.

Lonely Trail enters tapped.
{T}: Add {G} or {W}.
When Lonely Trail enters, you may put a loyalty counter on a planeswalker you control.

Whenever you cast a spell, if it doesn't share a name with a permanent or a card in a graveyard, draw a card.

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, until end of turn, you may spend mana as though it were mana of any color to cast spells with the same name as that card and spells with that name can't be countered.

[+1]: Return a land you control to its owner's hand. Create a tapped colorless land token named Far-Off Lands with “{T}: Add one mana of any color.”
[–1]: Discard a card. Return to your hand a card from your graveyard that shares a color with that card or a color of mana it could produce.
[–3]: For each color pair, you may pay that mana. Create X X/X green and blue Elemental creature tokens, where X is the number of times you do.

Whenever you gain life for the first time each turn, reveal the top card of your library. If it's a land or creature card, put it into your hand. Otherwise, put it into your graveyard.

When Machi's Assistants enters or you gain life, you may mill four cards. When you do, you may return a permanent card from your graveyard to your hand. This ability triggers no more than four times each turn.

Majestic Tomb enters tapped.
{T}: Add {B} or {R}.
When Majestic Tomb enters, you may put a loyalty counter on a planeswalker you control.

This spell can't be countered.
Flying, haste
Mayu, the Endless Flow gets +2/+2 for each spell you've cast this turn.

Target player reveals their hand and discards all nonland cards that share a name with a card in their graveyard. If no cards were discarded, draw a card.