You will need a 15-22 specific ambi safety such as the BAD *****
The standard AR type will pinch the lower as the lower is slightly wider than a regular AR. There are plenty of links and references on this site to help point you in the right direction.
Other add ons that are 15-22 specific include things like, Charging Handle. Charging handle Latch, Anti Walk/Rotation pins and Speed Bolt Release.
NDZ, Tacticool22 and KNS along with various other makers have plenty of bits to tempt you into spending your money.
Items like mag release buttons, trigger swap outs, muzzle breaks and flash eliminaters will fit as the threads on barrel are 1/2-28 so that alone will leave you LOTS of choice. Then there is hand guards if you are so inclined, for those you will need the barrel nut adapter and possibly the tacticool 22 wrench or make your own. The choice is yours and endless options are there to be had.
Have a browse and a read. Enjoy the rifle and the self torture of what to do next.
Rob.
