r/gamedev is pretty active, but it's more programmer/one man indie focused. Most people on this forum would probably be posting replies from an artist perspective, which is usually underrepresented there. They do love their free 2D tilesets for unity though.
There are a few that I follow but none of them seem to be very active.... https://www.reddit.com/r/3dmodeling https://www.reddit.com/r/computergraphics https://www.reddit.com/r/lowpolyTutorial https://www.reddit.com/r/Maya https://www.reddit.com/r/3dsmax https://www.reddit.com/r/Daily3D https://www.reddit.com/r/low_poly…