Arel is a Relational Algebra for Ruby. It 1) simplifies the generation complex of SQL queries and it 2) adapts to various RDBMS systems. It is intended to be a framework framework; that is, you can build your own ORM with it, focusing on innovative object and collection modeling as opposed to database compatibility and query generation.

Adds the missing outer_joins method to ActiveRecord

Extension for ActiveRecord that adds support for PostgreSQL array columns, mapping string values to integers.

Restrict the values assignable to ActiveRecord attributes or associations

Automaticaly increments an ActiveRecord column

Delayed is a multi-threaded, SQL-driven ActiveJob backend used at Betterment to process millions of background jobs per day. It supports postgres, mysql, and sqlite, and is designed to be Reliable (with co-transactional job enqueues and guaranteed, at-least-once execution), Scalable (with an optimized pickup query and concurrent job execution), Resilient (with built-in retry mechanisms, exponential backoff, and failed job preservation), and Maintainable (with robust instrumentation, continuous monitoring, and priority-based alerting).

Power tools for ActiveRecord relations (scopes)

Instruments for Factory Bot

Preseed reusable data for factory girl

Adds query origin tracing to your logs.

https://github.com/tsukasaoishi/fresh_connection

Another business actions architecture for Rails apps

Build Relay-compatible GraphQL schemas based on ActiveRecord models

Rails style structure for GraphQL API.

Builds ActiveRecord outer joins from association paths and provides references to table aliases.

Double entry bookkeeping with Rails

A user-centric voting extension for Rails 3 applications.

Provides automatic deadlock retry and logging functionality for ActiveRecord and MySQL

Paperclip-Azure is a [Paperclip](https://github.com/thoughtbot/paperclip) storage driver for storing files in a Microsoft Azure Blob.

An extension to paper_trail, using this you can fetch actual object who was responsible for this change