Material Maker - Cross-platform, procedural texture generation tool.
Color Hunt - Curated collection of beautiful colors, updated daily
Substance Designer - Substance Designer is a node-based non-destructive application for material authoring.
Color Palette Generator - Enter the URL of an image and find its color palette
TextureLab - Free, Cross-Platform, GPU-Accelerated Procedural Texture Generator.
Colicious - A delicious color generator