Over the last several years, various forms of your question have been asked on this forum. Here is one topic, and if you search, you can find more. They are not specifically about buying, but about project ideas and vector files.
Etsy is a rich source for vector content and ideas, but be aware that some of the content is available for free from other laser/cnc/vector sites. It is often hard to determine the chicken-and-egg path. For example, I purchased some cool cat silhouette vectors from Etsy, but later found the same graphics on a public domain graphics website. I surmise that the seller simply repackaged public domain content. In other cased it is possible that the free content is “borrowed” from Etsy sells.
Much of the free vector content is in Corel Draw format…probably because that is the format used by may of the K40 laser cutters. I’ve had good luck converting Corel Draw to SVG using free online tools.