Nuclear Overlord: Standard Overlord after the Nuclear Tanks upgrade. Official designation is ZTZ-200H (H for Hé, which is Chinese for nuclear).
Nuclear Battlemaster: Standard Battlemaster after the Nuclear Tanks upgrade. Official designation is Type 88GH.
Emperor Overlord: Its advanced sub-systems were implemented into the entire Overlord fleet after the Global War on Terror whilst the actual Emperors were mothballed and/or exported. Its designation was ZTZ-200G (or ZTZ-200GH when upgraded).
Attack Outpost: Simply an up-gunned/up-armored variant of the regular Listening Outpost that contains fireports. Still operational to a certain degree.