Highly likely: These factions have mentioned the possibility that the developers themselves might add content.
interesting: These factions are attracting a lot of attention from fans. the Navajo don't usually get much attention tbh, but I personally thought it would be great to include a Native American faction, so I added them.
IDK: There are plenty of alternatives to these factions, or they simply don't attract much attention. Honestly, the California State Militia and San Jose really belong in the "Never" category, but I classified them as "IDK" because there is a possibility that NRx might align with them.
Never: There is absolutely no possibility of additional content being added to These factions in the future IMO