Are there any big projects still using SourceForge? I know "big" is a little subjective here, but it seems like most active projects have already migrated.
ScummVM, Inkscape and wkhtmltopdf seem to be hosted there.
ScummVM has been maintained on GitHub for a few years now: https://github.com/scummvm/scummvm
The downloads are still on SF, though. That's unfortunate.