I noticed that Undead Nation shut down most of their Road to Fiddler's Green servers back in November of last year (2023). I personally don't know of any active fan servers for Fiddler's Green, as I never got a chance to play it online in any capacity, so I'm not very familiar with the game's community. If any members of PCGamingWiki know of other fan servers for Fiddler's Green that are still active as of 2024, please consider adding that information into this page.
EDIT: there still seems to be at least three active servers on Undead Nation, but that's still nowhere near as many active servers that I remember seeing being hosted on the site before it was deconstructed in late 2023. To my memory there were several dozen servers hosted there prior to 2023. I haven't tested these new servers yet, so I don't even know if they are running properly.