Attributed to Professor Wolfe. She gave this list in her 329 class. I am offering this list with no expressed warranty for the validity of the info, as did she.
The way to use these is to find the model you want and use the coverter to convert to a format you can use with your 3D modeller.
And while I have your attention, anyone interested in trying NuGraf to see if it's any good?
Also, if you go to "Look Smart", you have some great resources under Computers and Internet>>Multimedia&Design. Please try it.