I don’t know if it’s production ready yet, but tangled.org is a really interesting take on a forge and I’ve been watching it for a while. It decentralizes the centralized parts of GitHub in a pretty neat way. The biggest problem with forges that aren’t GitHub is people need to make and manage all these different accounts for each place they contribute (which almost certainly will lower the amount of people who do. Maybe this is a good thing these days though...)

Tangled uses the identity stuff from atproto which lets the important stuff (git, CI, etc) be decentralized while people only need one identity to contribute (and you can self host your PDS too). So nothing ends up being reliant on a third party.