I discovered a clip art site giving away my Tudor Rose and Red Rose of Lancaster as free clip art. I sent them this message via their "Contact" page:
It has come to my attention that your website is currently offering "free clipart" of at least three of my designs and products. These are on the Tudor Rose Template page, namely the red and white Tudor Rose Card, red and white Tudor Rose Print, and red Tudor Rose Ornament. These appear at the following location: http://www.clipartbest.com/tudor-rose-templateMake no mistake, I will protect my rights.
Be advised I am the owner of copyright on these designs. Publicly displaying and distributing these designs without my permission is copyright infringement. Failure to immediately remove my designs and cease unauthorized distribution of my copyrighted designs through your "free clipart" website will result in legal action.