One album which hasn't been explicitly mentioned yet is
Hoshi no Kirby ~Yume no Izumi no Monogatari~ / Mako Miyata. A complete copy sold today for 156,000 yen (
YJA link). Incomplete copies also regularly go for 100,000 yen.
This album is pretty hard to find complete, and it's for an iconic game, so I'm not surprised by the high price.