PlaceIMG - Placeholder images for your project in progress. Custom URLs generate placeholder pictures in various sizes with categories and effects.
PlaceKitten - Dead-easy placeholder images. Of kittens.
Placeholder.com - Placeholder.com generates custom placeholder images on the fly.
Dummy Image - Dynamic Dummy Image Generator
Videvo - Free HD stock footage & motion graphics for any project!
Lorem Picsum - Lorem Ipsum... but for photos