Ruby on Rails

Track changes to your rails models

Object-based searching.

Elasticsearch integrations for ActiveModel/Record and Ruby on Rails

Audited (formerly acts_as_audited) is an ORM extension that logs all changes to your Rails models.

Annotate Rails classes with schema and routes info

AASM - State machines for Ruby classes (plain Ruby, ActiveRecord, Mongoid, NoBrainer, Dynamoid)

SQL Server Adapter For Rails

SQL query builder, written in c#, helps you build complex queries easily, supports SqlServer, MySql, PostgreSql, Oracle, Sqlite and Firebird

Database Sharding for ActiveRecord

The minimalist framework of RESTful(server and client) - Resty

JRuby's ActiveRecord adapter using JDBC.

pg_search builds ActiveRecord named scopes that take advantage of PostgreSQL’s full text search

Easy activity tracking for models - similar to Github's Public Activity

ActiveRecord connection adapter for PostGIS, based on postgresql and rgeo

Easily and efficiently make your ActiveRecord models support hierarchies

Date and time validation plugin for ActiveModel and Rails. Supports multiple ORMs and allows custom date/time formats.

Versioned database views for Rails

Turbo-charged counter caches for your Rails app.