I was nuts about collecting stones and pebbles as a kid. Would have my pockets filled with big chunks of asphalt, rocks, pebbles, stones, etc. Idk it was def not normal, lol but I stopped. I would sometimes keep a piece of pebbel or twig though, if I found one that was exceptionally good when playing hopskotch and such. It needed to be kinda flat, but not too "skippy", so it needed a bit of edge to stop from rolling or skipping etc. It was a whole thing.
I do collect one if I find a cute one, and I also collect like broken, sanded down, glass at the beach (veryyyy rare to find), or maybe a shell or similar (the empty, clean picked ones. we dont really have those critters that uh swap shells or whatever?) We dont have that many shell types here tho, and I dont dont like to collect double of these, so if I have a nice one, I leave whatever I find. I dont like to hoarde natural resources, lmao.
My fave "pebble" tho to collect, is hardened slag. lol. I live in an industrial town where they use uhhh, like the spillover/foam/idk of molten slag?? or something?, to let it solidify and then use as filler around where they'd normally use pebbles/rocks/whatever. I cannot with english today it seems, sorry, hahaha. They have a really nice smooth surface, like glass, and are often in different colors, like black and torquise striped etc. They look absolutely gorgeous. I sometimes see tourists pick em up if they find them (you kinda gotta know where to look lol even if they are everywhere).
We also have a lof of rocks with "mica" (??) or whatever type of glittering/shimmer in rocks. Which makes for nice trinkets... but as someone who doesnt want to spend a fortune on safe rocks for aquariums, it sucks hahaha.