Here are some Resources regarding Geometry Dash

RobTopGames Website: https://robtopgames.com

Geometry Dash Demon List: https://pointercrate.com/demonlist

Official Geometry Dash Discord Community: https://discord.gg/geometrydash

GDColons Tools:

GDBrowser: https://gdbrowser.com

GD Icon Kit: https://gdbrowser.com/iconkit

GD Comment Generator: https://gdcolon.com/gdcomment

GD Font Generator: https://gdcolon.com/gdfont

GD Spritesheet Splitter: https://gdcolon.com/gdsplitter

might add more later, if I missed something important or links are wrong you can write it in the comments.