I’ve started a side project which is giving away illustrations with source files. They are free to use
for personal and commercial projects.
Go here - Sketchables
Finally, if you are looking for a particular design for your own project - post here and I’ll see if I
can get one done for you. There’s no charge while I’m still experimenting with the site
Hit me with any feedback too. I started this after not finding sketches I wanted in the generic stock photos / icons sites.