@ryo The site that I linked has SDL tutorials entirely in C. Parallel Realities is a FOSS game development team that writes their games entirely in C.
@ryo You should also check out Masahiro Sakurai's (creator of Kirby and Super Smash Bros) YouTube channel. He focuses more on game designed rather than game programming (mostly because getting technical could reveal trade secrets), but his videos are pretty interesting.
https://invidious.poast.org/channel/UCv1DvRY5PyHHt3KN9ghunuw
But I have very politely stolen his videos for offline viewing, but don't tell anyone, it's a secret.