Quiver came from Notch's older games, and it probably kept in there for nostalgia sake. The first marker is used, the others might have been unused since they didn't program such complexity. But if they do make writable books, they might add marking maps. The original moon stays as a backup. Footprint is unused because it looks so weird, although they might want to use it sometime if they make it look right. I'm pretty sure water color is used, especially in Swamp-to-Other transitions. I always thought the door texture was actually used, but I was likely just not paying attention. Probably used for nostalgia's sake as well. The last one I thought was part of old Experience orbs, but that's probably wrong.
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