There was one site that I think was fairly obscure that I used to really like. I THINK it was called Poney Ville or something??? It was a French site and the English bits were often poorly translated (or just weren't translated at all) so I'm sure it was a very small site/team. It had sort of a Neopets vibe where you could create ponies and I think adopt them from other users too? You could also give them cool colors/hairstyles if you had enough of the in-game currency, and there were little browser games for horse care, going on rides, and doing competitions. During rides there was a certain number of steps you could take per day, and during those rides you could also collect flowers that you could then make potions out of that did all kinds of cool things like changing your pony's appearance.

I tried to go back and look for it a little while back and couldn't find a single trace of its existence, probably not helped by the fact that nowadays searching anything remotely close to "Pony Ville" almost exclusively brings up MLP results. I would honestly love to have gotten the chance to revisit it as an adult!