When the crap hits the fan what accessories would you want on your AR-15?
For OPSEC and to keep our name off extra paperwork lets ignore silencers and short barreled rifles.
Silencers may play an important role in surviving a Post-SHTF world, but paperwork is also an OPSEC issue. Anyone having access to the right paperwork will know exactly who has a silencer and who has a short barreled rifle. Then there are the local, state and federal laws and restrictions.
For the sake of discussion and to keep things simple, lets just exclude anything that requires paperwork.