This is not everything. Just some of my favorites and from easiest and guaranteed spot to snatch. There are still many rare ones out there.
Tips: If your targeted vehicle is inside a hostile base, kill everyone, destroy the rest of vehicles in there before leaving. This way, the vehicles will respawn when you left the area. You can safely steal them again in case you broke it and when you do, you don't need to destroy other vehicles anymore. No hostile NPCs will respawn until you KIA.Unidad 4x4
Twin Propeller Airplane
Unidad Buggy, ATC, Gunboat, Unidad standard vehicles
Unidad Chopper. Missile variant
SB Standard Helicopter with Missile Launchers (recommended to try)