Fang of the Pack

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
At the beginning of combat on your turn, another target creature you control gains melee until end of turn. (If a creature has multiple instances of melee, each triggers separately.)

Vivien's Stampede

Each creature you control gains vigilance, trample, and melee until end of turn. (Whenever a creature with melee attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
At the beginning of the next main phase this turn, draw a card for each player who was dealt combat damage this turn.

Wulfgar of Icewind Dale

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
If a creature you control attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Deputized Protester

Menace (This creature can't be blocked except by two or more creatures.)
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)

Grenzo's Ruffians

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Whenever Grenzo's Ruffians deals combat damage to an opponent, it deals that much damage to each other opponent.

Menagerie Liberator

Trample
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)