Targaryen Dothraki Outriders: A Song of Ice & Fire

The Dothraki Outriders are generally used as scouting forces, using their superior riding skills to spy on the enemy and ascertain the best way for the main army to attack. But once the battle has started, a whole new facet of the unit becomes apparent: they're also master archers. Archers are generally slower units in an army. Obviously, that's not the case when your archer is also a master rider.