Gitea (what Forgejo forked from) recently stole the sidebar on repos from GitHub and I think that would be great for Forgejo to steal too…
Forgejo themed by Codeberg: https://codeberg.org/forgejo/forgejo (the codeberg theme is extremely low contrast)
Forgejo default: https://v15.next.forgejo.org/pparaxan/quark
Forgejo themed by Lix: https://git.lix.systems/lix-project/lix
Gitea: https://gitea.com/gitea/awesome-gitea
Gitea themed by Blender: https://projects.blender.org/blender/blender
I personally like Blender’s Gitea theme better than the rest but I guess that’s subjective. In dark mode I do not like the low contrast Codeberg theme or the default Forgejo theme, but all of the instances custom themes look great.
As far as Git forges go in general though.. tangled is very pretty https://tangled.org/tangled.org/core I think more power user oriented software should be comfortable with compact interfaces