elfin hollow
Me and my friends all use xaero's worldmap, but our maps don't sync, because the mod is entirely client-side. I knows I could use stuff like bluemap or dynmap to have a synced map in the browser, but those are really heavy on the server and require you to have you browser open, rather than just hitting a keybind in game.
It would be very cool to have a xaero's worldmap addon for servers that simply takes the map from the client (the client would still generate it, I guess, and merges it with whatever it previously had. And of course, it sends this map back to the other users as well, so that each player's worldmap is synced on servers that run this addon.
obsidian iron