Skipping Stone Wizards are muscular and dexterous and can skip even regular stones incredibly long distances. The great Fingers Fim was said to have skipped a perfectly normal stone all the way across the world ocean and back again.
Of course, a true Skipping Stone Wizard does not even need water for their feats. Easily skipping stones off any surface.
The heavier the stone the more powerful the spell, some stones are so massive they have to be thrown like a shot put. Stones must be recovered to cast them again...
You can skip stones at improbable angles and distances. As well if using spell stones you can conjure up a magical effect. Given time you can always find 1d6 smooth skippable stones in most environments.
Stone Pouch (looks like a sporran), Stone Polisher
Magic Missile - a medium stone, slightly pointy, magic bolts hit whoever was nearest where the stone hit
Fireball - a large slightly charred stone, does what is says on the tin
Freeze - a small cold stone, freezes any water it bounces off of, with skill you could make a bridge
Drag - a medium stone, any loose objects in a 10 ft cone gets pulled along with it until it stops
Teleport - a absolutely massive stone, teleports you to where it lands