Nemesis Mask

All creatures able to block equipped creature do so.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery. This card enters unattached and stays on the battlefield if the creature leaves.)

Llanowar Elves

Seton's Desire

Enchant creature
Enchanted creature gets +2/+2.
Threshold — As long as seven or more cards are in your graveyard, all creatures able to block enchanted creature do so.

Frost Giant

Rampage 2 (Whenever this creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Fyndhorn Elves

Gorilla Shaman

{X}{X}{1}: Destroy target noncreature artifact with mana value X.

Wolverine Pack

Marhault Elsdragon

Rampage 1 (Whenever this creature becomes blocked, it gets +1/+1 until end of turn for each creature blocking it beyond the first.)

Craw Giant

Trample
Rampage 2 (Whenever this creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Gorilla Berserkers

Trample; rampage 2 (Whenever this creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)
Gorilla Berserkers can't be blocked except by three or more creatures.

Beastmaster's Magemark

Enchant creature
Creatures you control that are enchanted get +1/+1.
Whenever a creature you control that's enchanted becomes blocked, it gets +1/+1 until end of turn for each creature blocking it.

Gorilla War Cry

Cast this spell only during combat before blockers are declared.
All creatures gain menace until end of turn. (They can't be blocked except by two or more creatures.)
Draw a card at the beginning of the next turn's upkeep.

Fires of Yavimaya

Creatures you control have haste.
Sacrifice Fires of Yavimaya: Target creature gets +2/+2 until end of turn.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Rancor is put into a graveyard from the battlefield, return Rancor to its owner's hand.

Raging Gorilla

Whenever Raging Gorilla blocks or becomes blocked, it gets +2/-2 until end of turn.

Aerathi Berserker

Rampage 3 (Whenever this creature becomes blocked, it gets +3/+3 until end of turn for each creature blocking it beyond the first.)

Balduvian War-Makers

Haste
Rampage 1 (Whenever this creature becomes blocked, it gets +1/+1 until end of turn for each creature blocking it beyond the first.)