UI Movement - The best UI design inspiration, daily
match.color.io - Automatically match colors of any image or movie with ML
UI8 - Carefully crafted UI design assets
Image Colour Transfer - A free-to-use browser-based application that allows an image to be recoloured to match the colours of another image using novel methods.
UI Garage - Specific mobile and web design patterns for your inspiration
Color Palette Generator - Enter the URL of an image and find its color palette