You should be able to browse a list here. Mastodon.social is the biggest instance I believe, but most will recommend choosing a server more suited to your particular location or interests.
Among the biggest there are mastodon.social, mastodon.online, mstdn.social, mas.to and mastodon.world. As usual I guess it would be preferable to join in a not so big instance as to reduce centralization. The local/federated timeline is the wild west anyway, its built on your follows.
Granted I never used Twitter so I might be using Mastodon wrong.
What's the condescending attitude for? 🤨 I legit don't know a single thing about the platform, my bad for asking recommendations as a new user like the normal average Joe?