Bitwise

Virtus

[DISCONTINUED ] Attributes on Steroids for Plain Old Ruby Objects

Hashie

Hashie is a collection of classes and mixins that make Ruby hashes more powerful.

Hamster

Efficient, Immutable, Thread-Safe Collection classes for Ruby

Addressable

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. It is flexible, offers heuristic parsing, and additionally provides extensive support for IRIs and URI templates.