Hi marcincon,

If you click on this link, you will find some leaf molds
on Ebay. Good luck.

Robb

Here is a link that might be useful: Ebay auction

marcincon, someone on this forum used silk leaves but I don't remember the results. Try doing a search on this forum and the "gallery" side.
You can use houseplant leaves or stop at a nursery and ask for the leaves that they are going to prune.
Whatever leaves you end up using make a test tile of the leave or part of the leaf first. Some leaves look like they would make great imprint and don't. I'd hate to see you make the birdbath and the imprints not work out. Billie