Welcome to the site and to black rifles. A little less than a year ago I got the bug for an AR and started hanging out here to gather info. This site is a great resource and you will find more information here than you can imagine. As far as accessories, you are correct, there are more than can fit in a thousand replies, however, some of the "standards" include optical sights (red dots, reflex sights, scopes, etc.), picatinny rail handguards (so you have a place to mount all your new toys), replacement stocks, tactical lights, vertical hand grips, bipods, etc. I would suggest taking a look at various picture threads on the boards so you can get an idea of what folks are using and how they are using some of these items. Depending on the type of shooting you do some of the accessories might work well for you while others will just add weight and/or clutter. Hope you enjoy your new rifle!