Foundry offers a great selection of open source SVG illustrations, created by the designers at thoughtbot. Free to use on your next project.
Mix-&-match illustrations of people with a design library, easily customizable. Free for commercial or personal use, created by Pablo Stanley.
10+ Free absurd illustrations that make sense in .png format. Take every user on an individual journey through their own imagination.
Many Pixels offer royalty-free and customizable SVG illustrations, every week, to power up your projects.