Whenever a player casts a spell, counter that spell unless that player pays , where X is the number of cards in all graveyards with the same name as the spell.

, : Chainflinger deals 1 damage to any target.
Threshold — , : Chainflinger deals 2 damage to any target. Activate this ability only if seven or more cards are in your graveyard.

Enchant land
Enchanted land has ", Discard a card: Gain control of target creature until end of turn."

Whenever you win a coin flip, put a luck counter on Chance Encounter.
At the beginning of your upkeep, if Chance Encounter has ten or more luck counters on it, you win the game.

, Mill a card: For each colored mana symbol in the milled card's mana cost, add one mana of that color. Activate this ability only any time you could cast an instant. (For example, if the card's mana cost is , you add .)

Create a 1/1 green Squirrel creature token.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flying
Threshold — As long as seven or more cards are in your graveyard, Childhood Horror gets +2/+2 and can't block.

At the beginning of your upkeep, you may put a +1/+1 counter on Chlorophant.
Threshold — As long as seven or more cards are in your graveyard, Chlorophant has "At the beginning of your upkeep, you may put another +1/+1 counter on Chlorophant."

Exile target card from a graveyard.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flying
Cognivore's power and toughness are each equal to the number of instant cards in all graveyards.

Draw three cards.

Whenever a player discards a card, you may gain 1 life.

, Discard a card: Crashing Centaur gains trample until end of turn.
Threshold — As long as seven or more cards are in your graveyard, Crashing Centaur gets +2/+2 and has shroud. (It can't be the target of spells or abilities.)

Sacrifice Crypt Creeper: Exile target card from a graveyard.

: Add .
, : Add .

Choose any number of creatures target player controls. Choose the same number of creatures another target player controls. Those players exchange control of those creatures. (This effect lasts indefinitely.)

Flying
Whenever Cursed Monstrosity becomes the target of a spell or ability, sacrifice it unless you discard a land card.

, : Add .

, , Sacrifice Darkwater Egg: Add . Draw a card.

At the beginning of your upkeep, exile a card from your graveyard.
Threshold — As long as seven or more cards are in your graveyard, Decaying Soil has "Whenever a nontoken creature is put into your graveyard from the battlefield, you may pay . If you do, return that card to your hand."