Kind of hard to tell you what you want unless YOU know what you want.
I could go so far as to say, get a heavy ass PEQ2 which I think might look cool but others not so much.
However, most people end up getting Magpul stuff for their rifles.
I'm a lot more simple and minimalist and have a set of minimalist KAC BUIS sights (BUIS post and micro iron sights, or BUIS post and triangle sight), and a Tango down vert grip that I use as a barricade support more than a grip. You could get a cheap red dot even.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE