As it turns out, other laser maunfacturers post free design files in common formats for non-commercial use. These are often quite useful, when they list the material, power, and speed used. Makes setting up your own database a bit easier!
although it can be tricky with the free sites. sometimes it is an istockphoto (or similar) image re-uploaded, and thus not actually free to use. Do an image-search before using stuff for commercial purposes, to see if it is protected by copyright, and to make sure it hasn’t been used to death already.
Also… do you mean absolutely free? or royalty-free?
(Royalty-free kind of implies that you are willing to pay a one-time fee.)