Echoing Return

Return target creature card and all other cards with the same name as that card from your graveyard to your hand.

Swamp

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Rat Colony

Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Power Word Kill

Destroy target non-Angel, non-Demon, non-Devil, non-Dragon creature.