PandocRuby is a wrapper for Pandoc, a Haskell library with command line tools for converting one markup format to another. Pandoc can convert documents from a variety of formats including markdown, reStructuredText, textile, HTML, DocBook, LaTeX, and MediaWiki markup to a variety of other formats, including markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, HTML slide shows, EPUB, Microsoft Word docx, and more.

Ruby/ProgressBar is an flexible text progress bar library for Ruby. The output can be customized with a formatting system.

This RSpec plugin makes it easy to mark test cases as pending or skipped for a specific Ruby engine (e.g. MRI or JRuby) or version combinations.

Slop provides a Ruby domain specific language for gathering options and parsing command line flags.

jaro_winkler is an implementation of Jaro-Winkler distance algorithm. It is written as a C extension and will fallback to a pure Ruby implementation on platforms where this is unsupported.

Test::Unit is unit testing framework for Ruby, based on xUnit principles. These were originally designed by Kent Beck, creator of extreme programming software development methodology, for Smalltalk's SUnit. It allows writing tests, checking results and automated testing in Ruby.

Ruby dubugging companion: pretty print Ruby objects to visualize their structure. Supports custom object formatting via plugins.

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments. It's built on top of Nokogiri and libxml2.

Gherkin-ruby is a Gherkin parser written in pure Ruby and less than 200 lines of code.

This package provides a collection of RuboCop cops to check for downstream compatibility issues in the Ruby code.

This package adds step-by-step debugging and stack navigation capabilities to pry, using byebug.

This package provides a Jekyll plugin to silently generate a sitemaps.org compliant sitemap for your Jekyll site.

stackprof is a fast sampling profiler for Ruby code, with cpu, wallclock and object allocation samplers.

Multicodecs is the ruby implementation of multiformats/multicodec, a canonical table of of codecs used by various multiformats.

Slim is a template language for Ruby that aims to reduce the syntax to the minimum while remaining clear.

CiteProc is a citation processor interface and citation data API based on the CSL specifications. To actually process citations, a dedicated processor engine is required: a pure Ruby engine is available in the citeproc-ruby gem.

The cane gem provides a great framework for running quality checks over your ruby project as part of continuous integration build. It comes with a few checks out of the box, but also provides an API for loading custom checks. This gem provides a set of additional checks.

Gettext is a GNU gettext-like program for Ruby. The catalog file (po-file) used is the same as that used by GNU gettext, allowing you to use GNU gettext tools for maintenance.

KPeg is a simple PEG library for Ruby. It provides an API as well as native grammar to build the grammar. KPeg supports direct left recursion of rules via the OMeta memoization technique.

crack provides really simple JSON and XML parsing, extracted from code in Merb and Rails.

WebMock allows stubbing HTTP requests and setting expectations on HTTP requests. This is useful when testing software.

This gem provides the classes LinkHeader and LinkHeader::Link, which represent HTTP Link headers conforming to RFC 5988. Objects can be constructed from and converted to text or a JSON-friendly Array representation. They can also be used to generate corresponding HTML link elements.

Erubi is a ERB template engine for Ruby. It is a simplified fork of Erubis

Pygmentize provides a simple way to call pygmentize from within a Ruby application.