Big fan of ManyPixels premium quality free illustrations, the license is super simple. Already using heavily with Ayro UI: http://ayroui.com/ Thanks guys for keeping this free!

I'm a big fan of Many Pixels. Started using the free illustrations and quickly moved to the paid service so that we could craft unique images that convey our message - service is fantastic, very responsive and so far great value for money.

Hey hunters! You probably know that illustrations are a great way to make your designs more interesting and modern. However, they can be expensive or difficult to come by. In our mission to make good design accessible to all, we’ve created our free illustration gallery. It currently hosts over 2000 designs, with new ones added every week! 🚀 How does it work? 🖐️ Illustrations can be found in 5 different styles: outline, monochromatic, isometric, flatline and two-color. 🎨 You can also easily change the color of each illustration to fit your brand directly on our website, and download a ready-to-use PNG file. 🐱‍💻 Or, grab an editable SVG file and make any desired changes. If you like our gallery, don’t forget to upvote it!!! 💙🙏