Placemat - Pretty nice placeholder images.
Web Gradients - Curated collection of 180 free fresh background gradients 🚀
Fill Murray - Custom-sized placeholder images of Bill Murray
CSSGradient.io - As a free css gradient generator tool, this website lets you create a colorful gradient background for your website, blog, or social media profile.
PlaceKitten - Dead-easy placeholder images. Of kittens.
Grabient - Grab a gradient