Repository Skaab

Exploit (When this creature enters, you may sacrifice a creature.)
When this creature exploits a creature, return target instant or sorcery card from your graveyard to your hand.

Meldweb Curator

When this creature enters, put up to one target instant or sorcery card from your graveyard on top of your library.

Ultimecia, Temporal Threat

When Ultimecia enters, tap all creatures your opponents control.
Whenever a creature you control deals combat damage to a player, draw a card.

Abuelo, Ancestral Echo

Flying, ward {2}
{1}{W}{U}: Exile another target creature or artifact you control. Return it to the battlefield under its owner's control at the beginning of the next end step.

Supreme Verdict

This spell can't be countered.
Destroy all creatures.

Agent of Treachery

When this creature enters, gain control of target permanent.
At the beginning of your end step, if you control three or more permanents you don't own, draw three cards.

Breaching Leviathan

When this creature enters, if you cast it from your hand, tap all nonblue creatures. Those creatures don't untap during their controllers' next untap steps.

Aetherspouts

For each attacking creature, its owner puts it on their choice of the top or bottom of their library.

Myr Battlesphere

When this creature enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Shipwreck Dowser

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Kishla Trawlers

When this creature enters, you may exile a creature card from your graveyard. When you do, return target instant or sorcery card from your graveyard to your hand.

Aberrant Mind Sorcerer

Psionic Spells — When this creature enters, choose target instant or sorcery card in your graveyard, then roll a d20.
1—9 | You may put that card on top of your library.
10—20 | Return that card to your hand.

Day of Judgment

Biblioplex Assistant

Flying
When this creature enters, put up to one target instant or sorcery card from your graveyard on top of your library.

Salvager of Secrets

When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Archaeomancer

Mnemonic Wall

Defender
When this creature enters, you may return target instant or sorcery card from your graveyard to your hand.