Cool Backgrounds
Cool Backgrounds offers a selection of beautiful, enticing image backgrounds to add to your blog post, website, or wallpaper. This free web tool is created by Moe Amaya a product designer based in San Francisco who builds resources for the design and development community.
Related Tools

Blobmaker
Blobmaker is a free design generator tool made by z creative labs, to help quickly create random, unique and organic-looking SVG shapes or blobs.

FakeClients
FakeClients is an easy-to-use, free tool for beginning designers to practice their design skills. You can generate clients for logo design, web design, graphic design and more.

Trianglify
Trianglify.io is a tool to generate low-poly, geometric (triangle) backgrounds, patterns, textures, and vectors, created by Quinn Rohlf.

Lorem Ipsum
Lorem ipsum is placeholder text commonly used in the graphic, print, and publishing industries for previewing layouts and visual mockups.