Or how about invisibility? Only a circle two spell!
Or how about a combination of both flight and invisibility? You only need to be a level 5 wizard/sorcerer to do that, and that combination makes you an absolute nightmare for a mundane character to deal with.
Regular invisibility ends if you attack, so it's not much use in prolonged combat unless you want to spend every other turn recasting it.
There are many, many ways to indirectly attack people without breaking invisibility.
"The spell ends if the subject attacks any creature. For purposes of this spell, an attack includes any spell targeting a foe or whose area or effect includes a foe. Exactly who is a foe depends on the invisible character's perceptions. Actions directed at unattended objects do not break the spell. Causing harm indirectly is not an attack. Thus, an invisible being can open doors, talk, eat, climb stairs, summon monsters and have them attack, cut the ropes holding a rope bridge while enemies are on the bridge, remotely trigger traps, open a portcullis to release attack dogs, and so forth. If the subject attacks directly, however, it immediately becomes visible along with all its gear. Spells such as bless that specifically affect allies but not foes are not attacks for this purpose, even when they include foes in their area."
A properly prepared wizard would not need to break invisibility. Ever.