Just look for the things that you are interested in. That's how i accumulated many of my followed accounts over time as well as subscribed subreddits over time.

You can also look for users under the same name on Mastodon and (hopefully) find them.

Please note that if you find an account you also followed on twitter and it ends with @bird.makeup, it's a bot mirroring tweets on Mastodon without mirroring your answers on Mastodon back to Twitter.