OR/AT tires, obviously.
LSD is okay, it's not an absolute requirement but if you are noticing your wheels slipping often in the way you drive, an LSD can help prevent that.
You can also look into metal skid plates. They can protect your oil pan, transmission, and other parts close to the ground from rocks/logs that may puncture them from underneath.
A winch can be helpful if you get stuck in mud or a deep ravine or something. Can help you get out by yourself instead of needing to wait for another person to show up and offer to use theirs.
Upgraded suspension or a lift can help too but its highly dependant on if you plan on only staying on roads or not. If youre only going on roads and trails, stock suspension is typically fine. Anything more than that and youll have to upgrade probably.
OR lights (LED) are also helpful if you plan to do a lot of night time driving.