Here you can download a CSV list of open-registration fediverse servers with more than 10,000 users for convenient silencing or blocking (less recommended, as this would permanently sever follow connections). This list is automatically updated on a hourly basis. The list of domains is also available in text format.
This can help combat spam and other annoying behaviour that tends to come from these kinds of servers.
Other numbers (rather than just 10,000) hopefully coming soon. If a instance is on this list in error, or missing from this list, please email me@wesleyac.com.