Where this has gained some degree of attention today for the #Universeodon (and by extension #MastodonAppUK folks)
I have made use, for a while now of the minimum block list provided by @oliphant - This list combines the public block lists of a number of mastodon instances including some that I personally have had previous issues with. However, the minimum list has proven to be almost always spot on when it comes to removing servers that are known to be problematic for a range of reasons.
A couple of weeks ago that list got imported here to Universeodon, and there were a small handful (5 maybe) servers that had some existing relationship which we severed as a result of the import, which was an intentional decision on my part.
The intention behind bringing the list in was to start to align our moderation with MastodonApp, but to also try to ensure we aren't reacting to reports constantly, and that we can prevent our community from having to see content that may be upsetting.