Exude Toxin

Each non-Dragon creature gets -X/-X until end of turn. (Then shuffle this card into its owner's library.)

Scavenger Regent

Scavenger Regent // Exude Toxin

Cadaverous Bloom

Exile a card from your hand: Add {B}{B} or {G}{G}.

Tainted Pact

Exile the top card of your library. You may put that card into your hand unless it has the same name as another card exiled this way. Repeat this process until you put a card into your hand or you exile two cards with the same name, whichever comes first.

Doomsday

Search your library and graveyard for five cards and exile the rest. Put the chosen cards on top of your library in any order. You lose half your life, rounded up.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle this artifact and your graveyard into their owner's library.

Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Doomsday Excruciator

Flying
When this creature enters, if it was cast, each player exiles all but the bottom six cards of their library face down.
At the beginning of your upkeep, draw a card.

Demonic Bargain

Exile the top thirteen cards of your library, then search your library for a card. Put that card into your hand, then shuffle.

Selective Memory

Search your library for any number of nonland cards, exile them, then shuffle.

Mirror of Fate

{T}, Sacrifice this artifact: Choose up to seven face-up exiled cards you own. Exile all the cards from your library, then put the chosen cards on top of your library.

Induced Amnesia

When this enchantment enters, target player exiles all cards from their hand face down, then draws that many cards.
When this enchantment is put into a graveyard from the battlefield, return the exiled cards to their owner's hand.

Scour for Scrap

Choose one or both —
• Search your library for an artifact card, reveal it, put it into your hand, then shuffle.
• Return target artifact card from your graveyard to your hand.

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

Demonic Consultation

Choose a card name. Exile the top six cards of your library, then reveal cards from the top of your library until you reveal a card with the chosen name. Put that card into your hand and exile all other cards revealed this way.