Comet (ability)

Comet is essentially a lesser version of Meteor.

Final Fantasy IV
Palom and Porom can cast Comet as a Twin spell. The Stardust Rod can also cast Comet.

Final Fantasy V
Comet and Comet2 are Time Magic spells.

Final Fantasy VII
Comet is found in a materia.

Final Fantasy IX
Vivi can cast Comet.