Two new mods were released recently, one for Zero Hour and the other for C&C3: Tiberium Wars. Both can be found at moddb or by clicking the respective link below.
C&C Tiberium Dawn Redux V1.3 is a Zero Hour mod which recreates all of the original Command & Conquer's units, themes, and even nine of the single player missions.
Over at Project Perfect Mod, Carnius has released Tiberium Essence V1.4, a total conversion mod for C&C3. This mod brings back some of the units from Tiberian Sun, adds new units, better looking tiberium, and high quality models.