Quaere - (You might) ask. Used to introduce questions, usually rhetorical or tangential questions
Qualem blennum! - What a doofus!
Qualem muleirculam! - What a bimbo!

Qualis pater talis filius

As is the father, so is the son; like father, like son

Quam bene vivas refert, non quam diu - The important thing isn't how long you live, but how well you live. (Seneca)
Quam se ipse amans-sine rivali! - Himself loving himself so much-without a rival! (Cicero)
Quam terribilis est haec hora - How fearful is this hour
Quandam - Formally
Quando omni flunkus moritatus - When all else fails play dead
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari? - How much wood would a woodchuck chuck if a woodchuck could chuck wood?