If you want to find out where a Mastodon instance is silenced/suspended, you can use this useful Google search string:

<instance domain> inurl:/about/more

where <instance domain> is the root domain of the instance you are checking.

You will get results from instances that have silenced/suspended the instance you are searching for, minus those with strict robot.txt or obfuscated domain names in the block list.

An informal measure of instance quality.