Dream Harvest

Each opponent exiles cards from the top of their library until they have exiled cards with total mana value 5 or greater this way. Until end of turn, you may cast cards exiled this way without paying their mana costs.

Fandaniel, Telophoroi Ascian

Whenever you cast an instant or sorcery spell, surveil 1.
At the beginning of your end step, each opponent may sacrifice a nontoken creature of their choice. Each opponent who doesn't loses 2 life for each instant and sorcery card in your graveyard.

Secrets of the Dead

Whenever you cast a spell from your graveyard, draw a card.

Emet-Selch of the Third Seat

Spells you cast from your graveyard cost {2} less to cast.
Whenever one or more opponents lose life, you may cast target instant or sorcery card from your graveyard. If that spell would be put into your graveyard, exile it instead. Do this only once each turn.

Rona, Sheoldred's Faithful

Whenever you cast an instant or sorcery spell, each opponent loses 1 life.
You may cast this card from your graveyard by discarding two cards in addition to paying its other costs.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Counterspell

Archmage of Runes

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, draw a card.

Mirrorform

Each nonland permanent you control becomes a copy of target non-Aura permanent.

Island

Sol Ring

Rug of Smothering

Flying
Whenever a player casts a spell, they lose 1 life for each spell they've cast this turn.