Sailor Moon is a mis-tagged artist name. Please do yourself and last.fm a favour and fix your tags placing only the proper artist name in your music "Artist" tag field.
Most of the background music (BGM) from the Sailor Moon anime was composed by 有澤孝紀 (Takanori Arisawa). The first opening theme was performed by ＤＡＬＩ, the second by Moon Lips, and the third by Kae Hanazawa. The English dub theme was performed by Nicole and Brynne Price. Searching the "related artists" on the pages of these musicians can probably yield the rest of the songs' performers.
Sailor Moon began as a manga created by Naoko Takeuchi in 1992 as a spinoff from her earlier work of Codename wa Sailor V. It ran in Nakayoshi from 1992 to 1995.
It was developed into the anime Bishoujo Senshi Sailor Moon in 1992. It spanned five arcs and the last episode aired in 1997. The japanese version produced approximately 38 cds, 2 boxsets, and countless character singles with Dali, Peach Hips, and Pretty Cast performing on most.