Okay, I hacked something together that tries to figure out if the people you (or somebody else) follows on Twitter have Mastodon account. Here it is: https://pruvisto.org/debirdify/

Very experimental. Not sure if I will keep it online forever. I'll put it on Github as well some time soon I think.

Debirdify

This is a web app that helps you find out which of the people you follow on Twitter are on Mastodon/in the Fediverse already and follow all of them easily.

@pruvisto Thanks so much for making this! Helped getting started in the fediverse so much easier. 🙏 Is there a way to buy you coffee or similar as a way to say thanks?
Debirdify (@[email protected])

Some people asked about donating money to #debirdify and the people who made it. We have enough money to run this service at the moment, so we would ask that you rather donate your money to a more worthy cause: e.g. your local Mastodon server or the Ukraine war relief efforts.

digitalcourage.social