Well i did too so here are some pistol attachments.

Pistol Red Dot- This is a red dot sight designed specifically to be attached to pistols. There really isn't much else to it.
+1 accuracy when firing at a target at close range. Costs 1000 dollars.

Pistol Scope Mount- This wonder of technology is, essentially, a piece of plastic, polymer, metal or other such material that allows one to mount a scope on a pistol.
Allows usage of any primary-only scope on a pistol. Costs 500 dollars.