Hatsune Miku, Voice of Joy

Creatures you control get +1/+0 and have vigilance
as long as you control three or more creatures.

Creatures you control also get +1/+0 and have
trample as long as you control six or more creatures.

Creatures you control also get +1/+0 and have
double strike as long as you control nine or more creatures.

(Original Card: Jetmir, Nexus of Revels)