Fin's AI Tweaks had a feature that gave enemy bots an armband based on the type of bot they were (Scav, PMC, Boss/Follower, ect).
I thought it was a pretty nice feature (especially when running as a Scav to better spot other Scavs) so I wanted to attempt to recreate it for myself (since it looks like FAIT is no longer being developed).

This is the result.

Pretty basic/barebones type mod, though does come with a config with a few changeable options.
Currently supported bot-types are: Scav (includes snipers and cursed), Raiders, Rogues, USEC, BEAR, and Bosses (includes all their followers and cultists)
Currently supported arm-bands are: blue, green, red, white, yellow, and purple (Twitch2020)

Known Issues:

Unfortunately certain clothing items will clip through armbands making them either very difficult to see, or basically invisible.

Fixing that is WAY beyond the scope of this mod (and more-so beyond my skillset), but I'll do my best to investigate a solution / workaround (if I can ever find the time).

If you would like to use this mod with SPT Realism make sure you load the Armbands mod AFTER (this can be done by putting a "z" at the beginning of the folder name) like so: "zDrewgamer-FactionIdentificationArmbands-x.x.x"

Installation:

Extract the "Drewgamer-FactionIdentificationArmbands-x.x.x" folder to your "\SPT\user\mods\" folder.

Updating:

DELETE the old "Drewgamer-FactionIdentificationArmbands-x.x.x" folder from your "\SPT\user\mods\" folder.
Extract the new version into your "\SPT\user\mods\" folder.

Uninstallation:

Delete the "Drewgamer-FactionIdentificationArmbands-x.x.x" folder from your "\SPT\user\mods\" folder.

Thanks/Credits:

Fin for the original idea.
All the great modders hanging out in the SPT Discord server (including, but not limited Lua, Chomp, and Fontaine).