While not a complete box set (missing the N64/PS and beyond games) it's still a massive retrospective look at the Ganbare Goemon series from the beginning, many of which either never saw actual releases or are very old and rare. Coupled with the fact that Goemon has had very limited exposure in the West this was an amazing opportunity to get acquainted with the music and the series and I am very thankful it was released. Hopefully they will do another box set with the newer era games!
Brave Frontier Original Soundtrack Complete Box
I picked this up on a random whim with no prior knowledge of the series or the composer and really fell in love with it. It is relatively simple melodies and music but it feels like a throwback to the SNES era. Hikoshi Hashimoto is someone I will be watching going forward.