Two big, vanilla instances are https://mastodon.social and https://mas.to. Unfortunately they've both been struggling to keep up with demand lately. If you're paralyzed by choice, I'd say just go for one of those if / when they're accepting new users.
I think Mastodon would get more signups if interested people were just pointed at like ten working, non-specialized, non-tiny instances, rather than being confronted with hundreds of weird / non-working options. I realize this feels a bit contrary to the goals of federation, but the current situation seems to be causing a lot of potential users to retreat in annoyance and confusion.
I think Mastodon would get more signups if interested people were just pointed at like ten working, non-specialized, non-tiny instances, rather than being confronted with hundreds of weird / non-working options. I realize this feels a bit contrary to the goals of federation, but the current situation seems to be causing a lot of potential users to retreat in annoyance and confusion.