If your up for more family-friendly fare there's Toontown Rewritten a continuation of the classic Disney MMO minus most of the copy-written character appearances.

To continue the discussion, I would like to include some others. There's Champions of Regnum, Salem: The Crafting MMO, Saga of Ryzom, Wurm Online, Eternal Lands, Tibia, Stendhal Online, Wakfu, Star Conflict, Second Life, Spellsworn, Stash, Gangs of Space, Mad World, Angeldust, Valiance Online, Time of Dragons, Relic Hunter Legends, The SKIES, Daimonin, Crossfire (MMO), Ryzom, Planeshift and WorldForge. There's probably more but those are what I can remember.

Last edited by Jared on 7 August 2020 at 3:32 pm UTC

Give Ryzom a try, it is native all the way down to being completely free and open source. I also think there is something really charming about its circa 2004 visuals and how that forced them (and games in general, at that time) to take an approach to stylization which worked out really well for fantasy games IMO.