• terraria.wikia.com — the largest wiki that's not associated with the author (I believe that association with the author is detrimental to a wiki, as the author can veto certain kinds of information, such as exploits)
• terraria.gamepedia.com — Bills itself as the "official" wiki. Is this because it's connected to TerrariaOnline.com? Or because it's connected to Re-Logic?
• ign.com/wikis/terraria

(I brought up this question in a forum here)