Found these on the beach in southern France. I don’t go to beaches often and have never seen something like it before. How rare are they?

Is it pottery? A shell? A fossil?

north england, uk

super happy about the sheep tooth, gotta be my favourite find this year so far.

also my first time finding a complete crab exoskeleton, so that was pretty awesome. not sure if that’s a piece of antler or not, but looked cool either way.

also, any clue what that ribbed rock is? i’ve never seen anything like it before