Blightbeetle

Protection from green (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything green.)
Creatures your opponents control can't have +1/+1 counters put on them.

Bayou Dragonfly

Flying; swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Ant Queen

{1}{G}: Create a 1/1 green Insect creature token.

Bond Beetle

When Bond Beetle enters, put a +1/+1 counter on target creature.

Blister Beetle

When Blister Beetle enters, target creature gets -1/-1 until end of turn.

Bane of the Living

Morph {X}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Bane of the Living is turned face up, all creatures get -X/-X until end of turn.