Customers could send you 4–6 match photos, then you turn them into a detailed black-and-white square collage like this and add their team names + final score.

For example: Nettleham 5–0 Moorlands

You could also offer: Player name • Team name • Match score • Date • “Man of the Match” • Cup Final

For a product listing, I’d call it something like “Personalised Football Match Photo Collage Slate Coaster”.

You could show customers a simple “How It Works” product image: 1. Order → 2. Send 4–6 photos → 3. Tell us the teams & score → 4. We create your collage → 5. Engraved onto slate.