The Content Security Policy (CSP) in Rails can get big fast. Slice it up with this gem.

SOAP XML/RPC Web service support for ActionController. Supporting ComplexTypes, SimpleTypes and Primitives

Translation engine for Rails applications

OAuth Core Ruby implementation

ZPdf allows to produce PDF content based on ERB templates. It easily integrates into a Rails application and operates on a paradigm very similar to Rails ActionMailer.

ZurbRush is a collection of Rails helpers and a form builder for Zurb Foundation 3.