Innovative and free publication platform
The currently most complete solution is probably the Open Science Framework, which doesn't yet support peer review but is planning to - and it can be somewhat simulated by using Hypothes.is. Then there are quite a few projects working towards this goal to some extent. Thus, a relevant follow-up question would be: with what reason are you looking for existing projects? To compare, to contribute, or to build upon? That would be relevant to what platforms we could suggest.

(That said, if you want to do some research on your own, I wrote an overview of alternative platforms a while ago.)