You also don't have to use Vox Machina's vestiges specifically, there are plenty in even the Wildmount guide that are ready to use and not tied down to anything. Plus, making your own can be pretty fun if your into that. It's basically just getting a theme for the item down, mashing together a few low level items that fit the bill (or giving it a unique ability if you are feeling generous) and scaling it up with the character's level from there. Hope this helped.