Loves/is loved by polymorphic belongs_to associations, Ransack, Squeel, MetaSearch...
Object-based searching (and more) for simply creating search forms. Not currently maintained.
A demo app using Ransack with Rails 5.1 and Ruby 2.3 to create advanced search forms.
Active Record, improved. Live again :)
ActiveRecord 3 query syntax on steroids. Not currently maintained.