Amy Diehl, Ph.D.Here's a Mastodon tool to search for users by name across instances. It also returns Twitter accounts in the results.
https://search.noc.social
https://search.noc.social
Teresa Chan | 陳敏怡 
@amydiehl is there a way to migrate or merge?
@tchanmd If you want to find Mastodon accounts for your Twitter follower or following lists (and then import into Mastodon) you can use the the debirdify tool. https://pruvisto.org/debirdify/
Tarkus