If you want something close to the GitHub UX, then Forgejo or Gitea.

If not, there are loads of options depending on your preferences and needs.

GitLab is still relevant. Personally I find it too resource-heavy (both server and web ui) to be my first pick but it's still widely used and actively developed.

For what part(s) of github?

Free as in freedom?

Many other tools/platforms provide decent source control and issue tracking. Nothing else has the FOSS project market share of github, and this matters especially when you're looking for the canonical home of a project and trying to judge how popular/active/viable it is (stars/commits/issues/PRs).

If you want exposure and participation for your FOSS project, it's harder to not use github.

FWIW, Forgejo does the source control stuff well. I love it for self-hosted local mirrors.

For small teams, fossil is unbeatable

https://fossil-scm.org

GitLab is very relevant. In some spaces, it is the only one with enough features. But it is pretty expensive and the way i see it, only the ultimate pricing plan makes sense. Premium makes no sense unless you are just a small company developing proprietary software with separate workflow for customers..

GitLab, Codeberg, SourceHut, Notabug, Radicle, Tangled… & that is just Git but there are other VCSs hosted other ways like Darcs, Pijul, Fossil, & so on.

I use codeberg