Military Style Rifles, US Made...
You've got AR-15s from Armalite, Colt, Bushmaster, DPMS, and others, though some use foreign made parts.
You've got M1 Garands and M1As from Springfield Armory, but there are foreign parts in both of them, if you care. SAR M1 Garands use Australian Lithgow receivers, I believe.
You've got the Ruger Mini-14 and Mini-30.
There are AR-10s from Armalite and other .308 cal AR rifles from makers such as Knight and DPMS.
You've got USGI M1 Garands and M1 Carbines, and rebuilds from places such as Fulton Armory and Orion 7 Enterprises.
You've got the AR-180 if you can find a preban, and the new Armalite AR-180B if you can't.
You've got the M96 Expeditionary Rifle and Recon Carbine from Robinson Armament (I think they've dropped the 18" carbine barrel).
That's really all I can think of...