Lists. The definitive list of lists (of lists) curated on GitHub.
RSpec Matchers Cheat Sheet. Interactive cheat sheet for Rspec matchers.
Sidekiq Statistic. See statistic about your sidekiq workers.
Debug/Mail. Easy to use mail server for developers.
Camaleon CMS. Camaleon CMS is a Ruby on Rails 4 based Content Management System, built as an alternative to wordpress for Ruby on Rails developers.
Rubocop. A Ruby static code analyzer, based on the community Ruby style guide.
Using a Rails' Mail Interceptor to Test Email. A great blog post that explain how to intercept emails in a Rails app.
Unicode Character Highlighter. A Sublime Text plug-in that highlights characters such as non breakable space, characters that often break compilers and scripts and is almost impossible to spot in the editor.
ActiveSupportTimeHelpers. Rails helpers to time travel.
Pokey. Pokey is a Ruby gem designed to easily simulate webhooks / other HTTP requests common to a production environment.