Every martial art, aside from brawling (autolearned) and bionic combatives (requires to memorize it while using the close quarter battle bionic) has a martial art book. However, not all of them spawn in the game, as far as I can tell. I’m not even sure if NPCs can teach martial arts anymore.
Stuff that has books that can be found in a world:
Krav Maga
Boxing
Tai Chi
Aikido
Karate
Taekwondo
Judo
Muay Thai (not really, but like bionic combatives it can be memorized via the same bionic)
Pankration (can’t be learned in character generation, but it has a book)
Melee weapon skills
Fencing
Niten
Silat
Eskrima
Medieval Swordsmanship
Ninjitsu
Basically, the books that don’t spawn so far, as far as I know, are the five animal kung-fu styles, the five venoms, Zui Quan, and Capoeira.
There’s also a debug style which you can only get if you debug in all martial arts. All it has is a weak fast attack and a slow powerful attack.