Discard a card: Putrid Imp gains flying until end of turn.
Threshold — As long as seven or more cards are in your graveyard, Putrid Imp gets +1/+1 and can't block.

When Hidden Horror enters the battlefield, sacrifice it unless you discard a creature card.

When Faceless Butcher enters the battlefield, exile target creature other than Faceless Butcher.
When Faceless Butcher leaves the battlefield, return the exiled card to the battlefield under its owner's control.

: Regenerate Twisted Abomination.
Swampcycling

Flying
Whenever Crosis, the Purger deals combat damage to a player, you may pay . If you do, choose a color, then that player reveals their hand and discards all cards of that color.

If there are ten or more creature cards total in all graveyards, this spell costs less to cast.
Fear
: Destroy target creature. It can't be regenerated.

When Terastodon enters the battlefield, you may destroy up to three target noncreature permanents. For each permanent put into a graveyard this way, its controller creates a 3/3 green Elephant creature token.

At the beginning of each upkeep, create a 1/1 green Saproling creature token.

Flying, first strike, vigilance, lifelink, protection from red and from green

Trample
Islandwalk
Shroud

Flying
Creatures can't attack you.

Choose a nonland card name. Target player reveals their hand and discards all cards with that name.
Flashback — Sacrifice a creature.

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

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

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Enchant creature card in a graveyard
When Animate Dead enters the battlefield, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Each player puts a creature card from their graveyard onto the battlefield.

As an additional cost to cast this spell, discard X cards.
Sickening Dreams deals X damage to each creature and each player.

Discard two cards: Create a 2/2 black Zombie creature token.

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Discard any number of cards. Target player reveals their hand, then you choose a nonland card from it for each card discarded this way. That player discards those cards.

When Diabolic Servitude enters the battlefield, return target creature card from your graveyard to the battlefield.
When the creature put onto the battlefield with Diabolic Servitude dies, exile it and return Diabolic Servitude to its owner's hand.
When Diabolic Servitude leaves the battlefield, exile the creature put onto the battlefield with Diabolic Servitude.

Return target creature card from your graveyard to the battlefield.
Flashback — Sacrifice three creatures.

: Add .
, Sacrifice Crystal Vein: Add .

Ebon Stronghold enters the battlefield tapped.
: Add .
, Sacrifice Ebon Stronghold: Add .

Polluted Mire enters the battlefield tapped.
: Add .
Cycling