Thank you for welcoming me, brother.
I have been looking into Shastar vidya for quite a while now (just very intrigued by Indian martial arts). Here are some of my thoughts/conclusions as per your request:
Firstly, there's Gatka. Many believe this is the traditional martial art of Kshatriyas and/or the Sikhs. However, this could be incorrect. There are no mentions of it in historical Hindu or Sikh writings. Gatka might just be the martial dance of the Muslim Hazara people. They way the move (check them out on YouTube) is quite fast and precise. It seems like its been in their culture for a while and they've really honed their skills. Doesn't look like they've simply copied Gatka from Sikhs and claimed it as their own. Gatka seems to be an entertainment form representing battlefield combat, rather than battlefield combat itself.
Then there's Gurdev Nidar Singh's Sanatan Shastar Vidiya/Chatka Gatka. I've read everything he's come out with and seen all his online vids (multimedia on old site, new site and YouTube). Very, very interesting stuff and I can listen to him for ages. However, he says his vidya was transmitted via oral tradition from, I believe, Baba Mohinder Singh. But I like textual evidence so that claims can be backed up. There are others out there like Yehoshua Sofer (teaches Abir, claiming its ancient Hebrew fighting arts), Ahati Kilindi Iyi (claims to teach African martial arts), Solomon Kaihewalu (teacher Lua, claiming its ancient Hawaiian martial arts), Masaaki Hatsumi (claims to teach the hand-to-hand art of the Ninjas), etc. But none (not even Hatsumi who started the Ninja boom), have ever presented any ancient or medieval textual evidence for what they teach.
Finally, the new 2017 Shastra vidya book authored by Harjit Singh Sagoo does contain textual evidence on the Kshatriya fighting arts. He's also drawn illustrations to go with the excerpts. The book's trailer can be found on YouTube:
https://www.youtube.com/watch?v=OuUz9GdBV9c
Got it from Amazon. Although, there's no mention of the animal/deity yudhans (forms) as taught by Gurdev Nidar Singh. But there is a variety of fist strikes, combat wrestling techniques and weapons strikes (both hand-to-hand and projectile). And all of these are based on descriptions from Hindu texts, such as the Mahabharat, Ramayan, Shukraniti, Nitiprakashik, Kamandakiya nitisar, Agni puran, Shiv dhanurveda, etc.
Bhul chuk maaf.