Nikara, Lair Scavenger

Partner with Yannik, Scavenging Sentinel (When this creature enters, target player may put Yannik into their hand from their library, then shuffle.)
Menace
Whenever another creature you control leaves the battlefield, if it had one or more counters on it, you draw a card and you lose 1 life.

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Out of Bounds

Assist (Another player can pay up to {3} of this spell's cost.)
Counter target spell.

True-Name Nemesis

As this creature enters, choose a player.
This creature has protection from the chosen player.

Swamp

Lórien Revealed

Draw three cards.
Islandcycling {1} ({1}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Bitter Triumph

As an additional cost to cast this spell, discard a card or pay 3 life.
Destroy target creature or planeswalker.

Huddle Up

Assist (Another player can pay up to {2} of this spell's cost.)
Two target players each draw a card.

Island

Snapcaster Mage

Flash
When this creature enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Emperor of Bones

At the beginning of combat on your turn, exile up to one target card from a graveyard.
{1}{B}: Adapt 2.
Whenever one or more +1/+1 counters are put on this creature, put a creature card exiled with this creature onto the battlefield under your control with a finality counter on it. It gains haste. Sacrifice it at the beginning of the next end step.

Blaring Captain

Partner with Blaring Recruiter (When this creature enters, target player may put Blaring Recruiter into their hand from their library, then shuffle.)
Whenever this creature attacks, attacking Warriors get +1/+1 until end of turn.

Torrential Gearhulk

Flash
When this creature enters, you may cast target instant card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Scrawling Crawler

At the beginning of your upkeep, each player draws a card.
Whenever an opponent draws a card, that player loses 1 life.

Genesis Chamber

Whenever a nontoken creature enters, if this artifact is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Grand Coliseum

This land enters tapped.
{T}: Add {C}.
{T}: Add one mana of any color. This land deals 1 damage to you.

Grudge Keeper

Whenever players finish voting, each opponent who voted for a choice you didn't vote for loses 2 life.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Overwhelming Denial

Surge {U}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
This spell can't be countered.
Counter target spell.

Will Kenrith

+2: Until your next turn, up to two target creatures each have base power and toughness 0/3 and lose all abilities.
−2: Target player draws two cards. Until your next turn, instant, sorcery, and planeswalker spells that player casts cost {2} less to cast.
−8: Target player gets an emblem with "Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy."
Partner with Rowan Kenrith
Will Kenrith can be your commander.

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Restless Reef

This land enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}: Until end of turn, this land becomes a 4/4 blue and black Shark creature with deathtouch. It's still a land.
Whenever this land attacks, target player mills four cards.

Bite of the Black Rose

Will of the council — Starting with you, each player votes for sickness or psychosis. If sickness gets more votes, creatures your opponents control get -2/-2 until end of turn. If psychosis gets more votes or the vote is tied, each opponent discards two cards.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")