In 1994, a mail order set was sold in Japan. Every few months a new CD would arrive to be added to the set, ending in 1995. Titles "Sweet Memory", the set had cool artwork, sort of Southern California inspired. It was a limited set and can be difficult to find and can be pricey if you do.
Each disc had a loose theme and the songs on that particular disc somewhat matched the theme.
In 2017, the set was released in Japan, this time as a box set and new, more simple artwork was included.
If you count their studio releases (minus Christmas) this 6-disc set includes 75% of their catalog.