Yahoo! Design Pattern Library Launched by Erin Malone, Matt Leacock, Bill Scott, closely tied to the YUI Library.

UI Patterns Anders Toxboe provides code examples and guidelines for common interaction patterns.

Welie.com - Patterns in Interaction Design Best practices that can be use when designing UX, collected by Martijn van Welie.

"Designing Interfaces: Patterns for Effective Interaction Design" A collection of patterns included in Jenifer Tidwell's book.

Konigi - Interface A resource for user experience designers, that includes examples of interface and visual design.

Elements of Design Different type of web design showcase focusing on specific aspects of web design.

Design Pattern Flickr Group Compare different approaches, finding existing and emerging patterns to design problems. [Morville] [Factoryjoe]

Open Design Patterns Florian Grassle shares proven Human-Computer Interaction design knowledge in an open community manner.

Web Patterns: A UC Berkeley Resource for Building User Interfaces Project advised by Bob Glushko as a resource to the U.C. Berkeley community of web developers.

User Interface Design Patterns One of the first pattern libraries (2003) containing GUI designs of common software, by Sari A. Laakso, University of Helsinki.

Pattern Tap Interface Design Collection for Inspiration and Fun.

UI Pattern Factory a mix of UI design pattern library and user interface gallery.

Interaction-Patterns.org a wiki collection of interaction patterns.