Keyword: Threshold

All creatures gain menace until end of turn. (They can’t be blocked except by two or more creatures.)
Threshold — If seven or more cards are in your graveyard, creatures can’t block this turn.

Fear (This creature can’t be blocked except by artifact creatures and/or black creatures.)
Threshold — As long as seven or more cards are in your graveyard, Frightcrawler gets +2/+2 and can’t block.

, : 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 creature
Enchanted creature gets +2/-2.
Threshold — Enchanted creature gets an additional +2/-2 as long as seven or more cards are in your graveyard.

, : Tap target creature.
Threshold — , : Tap two target creatures. Activate this ability only if seven or more cards are in your graveyard.

Otarian Juggernaut can’t be blocked by Walls.
Threshold — As long as seven or more cards are in your graveyard, Otarian Juggernaut gets +3/+0 and attacks each combat if able.

Threshold — Metamorphic Wurm gets +4/+4 as long as seven or more cards are in your graveyard.

Destroy all creatures. They can’t be regenerated.
Threshold — If seven or more cards are in your graveyard, instead destroy all creatures, then create two 1/1 white Spirit creature tokens with flying. Creatures destroyed this way can’t be regenerated.

Flying
At the beginning of your upkeep, mill a card.
Threshold — As long as seven or more cards are in your graveyard, Bloodcurdler gets +1/+1 and has “At the beginning of your end step, exile two cards from your graveyard.”

: Add . Barbarian Ring deals 1 damage to you.
Threshold — , , Sacrifice Barbarian Ring: It deals 2 damage to any target. Activate this ability only if seven or more cards are in your graveyard.

, 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.)

At the beginning of your upkeep, you may create a 1/1 green Squirrel creature token.
Threshold — Squirrel creatures get +2/+2 as long as seven or more cards are in your graveyard.

Target player sacrifices a land.
Threshold — Each player sacrifices all lands they control instead if seven or more cards are in your graveyard.

Enchant creature
Enchanted creature has first strike.
Threshold — Enchanted creature gets +3/+0 as long as seven or more cards are in your graveyard.

Enchant creature
Enchanted creature can’t attack.
Threshold — Enchanted creature can’t block as long as seven or more cards are in your graveyard.

White creatures get +1/+1.
Threshold — White creatures get an additional +1/+1 as long as seven or more cards are in your graveyard.

Threshold — Mystic Visionary has flying as long as seven or more cards are in your graveyard.

: Add . Centaur Garden deals 1 damage to you.
Threshold — , , Sacrifice Centaur Garden: Target creature gets +3/+3 until end of turn. Activate this ability only if seven or more cards are in your graveyard.

Trample
Threshold — : Regenerate Krosan Avenger. Activate this ability only if seven or more cards are in your graveyard.

Whenever Stone-Tongue Basilisk deals combat damage to a creature, destroy that creature at end of combat.
Threshold — As long as seven or more cards are in your graveyard, all creatures able to block Stone-Tongue Basilisk do so.

Whenever Stone-Tongue Basilisk deals combat damage to a creature, destroy that creature at end of combat.
Threshold — As long as seven or more cards are in your graveyard, all creatures able to block Stone-Tongue Basilisk do so.