The basic primordial beej mantra is “om”, it's the mantra from which all the other mantras ended up born. Each beej mantra has a selected god or goddess connected with them. The kinds of beej mantras are— Yog beej mantra, Tejo beej mantra, Shanti beej mantra, and Raksha beej mantra. https://hanumanshabharmantra90909.thezenweb.com/the-5-second-trick-for-beej-mantra-64374981