• RailsWarden
• warden-rspec-rails

• Devise

• Sinatra Warden
• Sinatra More - development has stopped
• Example Gist
• Another Example for Sinatra
• Sinatra with Warden Example
• Using Warden to Secure a Sinatra REST API
• Sinatra with Warden, ActiveRecord, and Postgres

• Padrino Warden

A collection of various authentication strategies can be found in Warden::Strategies

• An example Twitter OAuth strategy written by Ben Burket (wayback machine link)
• An example BCrypt strategy
• Comprehensive OAuth strategy - last check-in 2010
• warden-OpenID - last check-in 2010
• Google Cloud Identity-Aware Proxy strategy

• warden-browserid - depended on Mozilla's Persona (shut down in November 2016)