Most embroidery sites will have a free design. This is so you can test out how good their digitizing is.
As many site specialize in certain design types, if you can tell us what kind of designs you are looking for, we can probably direct you better (kids, redwork, applique, sophisticated etc.) A couple of my favorite sites are:
http://www.bfc-creations.com/
https://kreationsbykara.com/collecti...ess-treasures/ (she has some weird Halloween stuff on her home page today, but most designs are very elegant)