One common github repo is the stdlib itself which is where people seem to try to submit to first, but then too featureful/too hard to maintain gets pushback. Slightly more granular is stdlib+fusion, but I've never been sure that split had much value..Fusion mostly seems a staging area, and has also been much less active than stdlib & nimbleverse in general.
FWIW, most of The Nimbleverse is actually quite fresh/not stale.. Something like 60-70% by package count. I think this is all going back to the maybe not so well resolved ["Nim distribution" idea (link for newcomers)](https://github.com/nim-lang/RFCs/issues/173). The [fision package](https://github.com/juancarlospaco/fision) may be a better approach { although I prefer someone the English spelling "fission" :-) }. The general freshness may mean the underlying problem to be solved isn't so bad. Nim has great programmer/project retention/a low Abandonware Quotient. Anyway, this discussion is maybe getting slightly off track. Zlib (and its HTTP cousins) are very often in prog.lang stdlibs for the "Big Tent" stdlib approaches. On that basis alone, I think this work should be fast tracked to be a new stdlib module, maybe bypassing fusion entirely. (And I say this being no fan of the deflate algo. ZStd is much better. Deflate is just "standard".)