A better list of Mastodon servers that have pre-emptively defederated from Threads.net
Mastodon servers that have suspended Threads.net
https://fedipact.veganism.social/
https://fedipact.veganism.social/
I like the stance that fosstodon.org are taking: wait and see what happens, but if Threads introduces any issues that could negatively impact users, they will defederate.
For curiosity's sake, it's going to be interesting to watch open source and proprietary sectors of the Fediverse rub shoulders for a while.
This list seems curated, there are some huge servers missing, so the author probably decided to include whatever they thought was notable to them.