Copy or move Thunderbird Message Filters to several mail accounts, with QuickFilters
How would you like to copy your great message filters from the x mail account to a mail account you just created? Recreating all those rules can be a task you may prefer not to think about! Moving or copying message filters between several Thunderbird mail accounts is a functionality that unfortunately is not provided by Thunderbird itself, for whatever absurd reason. However it is something that can be done.
You can copy or move all or any of your message filters the tough way or the easy way. The tough way is to locate the files where Thunderbird stores message filters for an account, open them with the Notepa and copy any or all message filters from one file to another.
The easy and much more flexible and safe way, is to use this dedicated addon that will do precisely this job. It adds a toolbar in the Message Filters dialogue, with icons that let you perform several operations. Just select whatever you need to copy or move, then press the copy or cut icon, go to the destination account and use the paste button to copy or move the message filters of the source account.
Note that the addon is supposed to work for Thunderbird v. 60 and earlier, but I use it with the latest version without any problem! To feel safer, just backup your Thunderbird folder, at least the first time you use it.