Flockchaser Phantom

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Flying, vigilance
Whenever Flockchaser Phantom attacks, the next spell you cast this turn has convoke.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Flying, vigilance
Whenever this creature attacks, the next spell you cast this turn has convoke.

March of the Machine Commander

Convoke
Flying, vigilance
Whenever Flockchaser Phantom attacks, the next spell you cast this turn has convoke.