There's https://os.phil-opp.com/ https://os.phil-opp.com/ for rust, https://github.com/tuhdo/os01 https://github.com/tuhdo/os01 for general OS development and m

There's https://os.phil-opp.com/ https://os.phil-opp.com/ for rust, https://github.com/tuhdo/os01 https://github.com/tuhdo/os01 for general OS development and make sure to read Operating Systems: Three Easy Pieces