Scholar of the Lost Trove

Flying
When Scholar of the Lost Trove enters, you may cast target instant, sorcery, or artifact card from your graveyard without paying its mana cost. If an instant or sorcery spell cast this way would be put into your graveyard, exile it instead.

Mnemonic Deluge

Exile target instant or sorcery card from a graveyard. Copy that card three times. You may cast the copies without paying their mana costs. Exile Mnemonic Deluge.

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Gravebreaker Lamia

Lifelink
When Gravebreaker Lamia enters, search your library for a card, put it into your graveyard, then shuffle.
Spells you cast from your graveyard cost {1} less to cast.

Vega, the Watcher

Flying
Whenever you cast a spell from anywhere other than your hand, draw a card.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Yennett, Cryptic Sovereign

Flying, vigilance, menace
Whenever Yennett, Cryptic Sovereign attacks, reveal the top card of your library. You may cast it without paying its mana cost if its mana value is odd. If you don't cast it, draw a card.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Secrets of the Dead

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

Sol Ring

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

River Kelpie

Whenever River Kelpie or another permanent enters from a graveyard, draw a card.
Whenever a player casts a spell from a graveyard, draw a card.
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.)