This is call for all moderators of Mastodon instances with open registration policy: let's cooperate, let's fight botnets together. We can share mail domains and blocked IP addresses.
I am trying to keep registrations open for the next big wave of Mastodon migration, which I believe is inevitable.
There are very few actual humans, willing to do some sustained harm - most of the malicious activity are bots. And we can track where they register and operate from. Ultimately, we can learn who is doing this shit and who pays for it...