Is there a list of the 600 "collectives" that need to migrate to continue accepting donations? Do any of them already have alternative donation methods?
That's a LOT of groups! This page here indicates they were raising $13m a year back when they had 300, so it could be double that now: https://opencollective.foundation/
Early on, I had 'Drupal St. Louis' (a local meetup group) on the platform, and it was a huge help in our ability to put on a large-ish annual gathering. There's no other way we could've done it short of a very benevolent for-profit local company putting up all the resources.
Alas, that group slowly disbanded over the past few years, so luckily this announcement doesn't hurt us. But I have pulled out the last bit of funding we had left, and will donate it to a local tech foundation.
That's a LOT of groups! This page here indicates they were raising $13m a year back when they had 300, so it could be double that now: https://opencollective.foundation/