I do not know of such community but I want to encourage you to post in the existing FOSS communities, i don't think self promo would be badly received (ask the mods just in case) so don't be afraid to share your projects!
Please do post your projects in !opensource@lemmy.ml and similar foss related communities. Just because news is posted more often doesn't mean only news should be posted there! Projects don't tend to progress at the same pace news does anyway. If the folks there don't like it they will probably suggest an alternative.