Alpha Jackal - A upgraded version of the shotgun, Jackal, from Crysis 2.
Compound Bow - The Bow was introduced with the announcement of Crysis 3 to emphasize your "The Hunter". The bow and arrow will have multiply arrow upgrades which includes shock, incendiary, explosive and a special arrow just for stealth.
C4 - High Explosive featured in the at the end of the Crysis 3 E3 2012 Gamepaly Trailer.
Ceph Plasma Destroyer - A alien heavy weapon that fires large rounds of plasma.
Feline - A sub machine gun, that you will have early access to if you Pre-Order Crysis 3. The feline was the main weapon used by C.E.L.L. agents in Crysis 2.
Hammer 2 - Upgraded version of the hammer pistol, Hammer, from Crysis 2.
Jaw - A rocket launcher that has been in every single Crysis Game to Date.
Scar - A combat assault rifle that can be equipped with various attachments.
(The Scar has been used in every single Crysis Game to date.)
Typhoon - A new assault rifle that can go fully automatic which was showed off in the Crysis 3 E3 2012 Gameplay Trailer.
This list shall be updated as more information on Crysis 3 comes out.