Bluedoc
document management tool
forem
the platform that powers dev.to
Gem.sh
Beautiful documentation for any RubyGem
GitLab
self hosted Git management
Listed.to
online publications with automatic newsletters
Notebook Gallery
enterprise Jupyter notebook sharing and collaboration platform
OpenProject
project management system
Pig CI
Rails performance monitoring, plus CI
rubytoolbox.com
catalog of all Rubygems that keeps track of popularity and health metrics