Ruby

General Resources

Airbnb Ruby Style Guide.
Fast Ruby – Collection of common Ruby idioms.
Awesome Ruby

Packages

RubyGems – Find your packages here.
- Find popular recently updated Gems.
bundler – 4.7k – Manage gem dependencies.

Ruby on Rails

Rails – 44k – The famous web framework for Ruby.
RailsAdmin – For managing the back-end of Ruby on Rails applications.
Active Admin – 8.6k
Active Emailer
Active Job
Action Mailbox – Routes incoming emails.
Active Model
Active Record
Active Storage
Action Text – Rich Text Editing.
Active View
Action Pack
Action Cable
Active Support
Devise – Flexible authentication with Warden.
paper_trail – 5.6k – Track changes to Rails models.

Static Generators

Jekyll – 38.5k

Web Frameworks

Sinatra – 10.7k
rack – 3.7k – Modular web server interface.
faraday – 4.5k – HTTP/REST API client library
sprockett – .7k – Rack-based asset packaging system.
addressable – 1.2k – Alternative URI implementation.
haml – 3.4k – HTML Abstraction Markup Language.
will_paginate – 5.4k – Pagination.
simple_form – 7.5k – Forms easily.
grape – 8.9k – REST-API building framework.

Web Servers

puma – 5.9k
unicorn

Development, Testing, Etc.

webmock
logstash
httplog
rspec – For BDD
rake – Like Make.
minitest – Suite for TDD, BDD, mocking, benchmarking.
rubocop – 10.2k – static code analyzer and formatter.
faker – 8k – generate fake data.

Mail

postal – 9.2k – mail delivery ingoing and outgoing.

Other

i18n
thor – for building CLIs
tzinfo – for timezones
concurrent-ruby
dotenv – Load environment variables from .env files.
sidekiq – 9.8k – background processing.
resque – 8.6k – Redis backed library for creating background jobs, using multiple queues, etc.
fluentd – 8.3k – Unified Logging Layer.
whenever – 8.1k – Cron Jobs.

Popular Software Written in Ruby

Discourse – 28.9k – forums.
Vagrant – 18.8k – for creating and managing virtual machines for development.
Homebrew – 18.8k – package manager for MacOS/Linux.
Diaspora – 12.3k – distributed, privacy focused social network.
Capistrano – 11.2k – remote, multi-server automation.
Spree – 9.9k – ecommerce.
Chef – 5.9k – Systems Integration Framework.