Iron Man designs would be copyrighted so the only legal place that would have them is a vendors that can afford to pay for a license from the copyright holder to use the images of Iron man for the purpose of digitzing them for embroidery and also to sell the digitzed designs to the public.

I don't think you will find any legal designs available anywhere.
EastWitch2

just google iron man machine embroidery, quite a few come up

I think the designs on the bonanza link just posted here are illegal.
This vendor does not have permission or a license from the copywrite holder to use them.

If you purchase them you are breaking copyright laws also.
EastWitch2