Myself and the organization I head (Math Advance) use GitLab because of their beautiful groups/subgroups feature (yay nested directories!). You can find me at @chennis on GitLab and Math Advance at @mathadvance.
I still will use this account to send PRs to repos, collaborate, etc. But nothing serious, most likely.
I'm a high school junior that enjoys fiddling around with projects, particularly math-contest based ones.
My website is dennisc.net. You can learn more about my coding projects there, if you are so inclined.