Regarding the question itself, Starbound and Minecraft. Maybe Final Fantasy XII if I was to play it multiple times, as I take at the very least 100+ hours to finished it, and 250+ if I'm not in a hurry.
But regarding gaming fatigue, perhaps it could be a symptom of playing too much of only a handful of game styles? If you wouldn't mind, may I suggest to check some smaller games in length and scope, specially indies? Those tend to be rather diverse in their scopes and executions.