I have contributed to the following repositories in the recent past:
coronasafe/journal is a web application used for contact-tracing. The application is built on React and Rails.
Terrastories is a geo-storytelling application built to enable local communities to locate and map their own oral storytelling traditions about places of significant meaning or value to them.
Muskrat is an mqtt pub-sub message processor for Ruby. It is a pure Ruby library and uses actor model.