Sacred Guide is a pretty unique form of card draw. Fossil Find lets you reorder your graveyard, which is pretty weird. Helix Pinnacle is rather singular as well. And there's no Hive Mind like Hive Mind, although some cards are vaguely similar. Glacial Chasm is not the only land that doesn't tap for mana, but it's pretty weird and singular for several reasons. Dryad Arbor is far from the only man-land, but it is still the only one quite like it. Arixmethes, Slumbering Isle shares a little bit of space with it, but it too is rather singular.
Low-power cube enthusiast!
My 1570 card cube (no longer updated)
My 415 Peasant+ Artifact and Enchantment Cube
Ever-Expanding "Just throw it in" cube.