Interfacer - Collection of more than 200+ free design resources
Patterninja - Create patterns online
Facebook Design Resources - A collection of free resources made by designers at Facebook
Doodad.dev's Pattern Generator - A free tool for creating unique, royalty-free, repeatable patterns.
Freebiesbug - Collection of the best free web design resources.
Pattern Monster - Pattern Monster is a pattern maker app to create vector patterns for your projects