replacements.com might be some help to you.

Can you get a clearer picture of the backstamp/

The backstamp says Bavaria Schumann

Pretty! Check Etsy as well. Not the same but might give you search word ideas.

It's not onlyw hat it says, but how it's configured....

@lindac92 is correct - here's a link that explains the difference in backstamp design for Schumann; the format (color/design) of the backstamp is your first clue in the age of the piece, and ultimately the pattern name: https://www.efineantiques.com/Schumann%20Tables.htm

Yours is blurry, but looks like it's from after 1900. I also noticed that this serving piece doesn't have the pierced rims or ornate gold painting like earlier Schumann pieces, but sometimes the serving pieces don't (this is a drawback to the photo-pattern search on Replacements - they only show the thumbnail of the dinner plate, which can look different from other pieces in a set).

Once you have that info, you can scour Etsy, Chairish, 1st Dibs and eBay for the pieces you need. I set up alerts on these so that when someone posts a new piece from a collection I have interest in, I can check it out. Welcome to my other pricey obsession besides real estate. :)

I found only this one https://www.ebay.com/itm/353116871896