Okay, yeah I'm actually not sure how many ost's and singles there are for sailor moon but I'm sure there's a wiki for that somewhere. I hear the musicals have a few songs unique to them so if there are any soundtracks for those then I have a lot of music I still haven't heard.
There are a ton, but a lot is also duplicated. For example, you don't really need all the various OP/ED collections. You'll pretty much have everything minus some karaoke and dialogue tracks with the following...
BGM:
Sailor Moon Memorial Music Box
Sailor Moon Music Collection Extra Version
(Note: some BGM tracks, like what plays at the start of ep 150, are simply not available on soundtrack)
Vocal albums:
Sailor Moon Memorial Song Box
Sakurakko Club - La Soldier single
Sailor Moon R Maiden's Poems Collection
Sailor Moon S UNC Plus
Sailor Moon Sailor Stars Merry Christmas
Sailor Moon Supers Christmas For You
Sailor Moon Supers in Paris
Sailor Moon Choral (the one by Society of Kalmia)
(Note: first Stars ED is not available on disc)
Misc instrumental:
Sailor Moon Music Fantasy
Sailor Moon Brass Fantasy
Sailor Moon R Symphonic Poem
Sailor Moon S Music Fantasy
Sailor Moon Supers Orgel Fantasia
Sailor Moon Supers Piano Fantasia
Games OSTs:
Sailor Moon Game Music
Sailor Moon R Game Music
Sailor Moon S Game Music
Sailor Moon S Game Music PSX/Saturn Version
Sailor Moon Another Story
Drama albums:
Sailor Moon Sound Drama Collection 1 (Ikuhara directed!)
Sailor Moon Sound Drama Collection 2 (Ikuhara directed!)
Sailor Moon Sound Drama Collection 3 (Ikuhara directed!)
Sailor Moon R Sound Drama Collection 1
Sailor Moon R Sound Drama Collection 2
Sailor Moon S Sound Drama Collection
Live action:
PGSM DJ Moon 1
PGSM DJ Moon 2
PGSM DJ Moon 3
PGSM Moonlight Real Girl
Plus some Musical albums I've never really gone into.
I like Kotono Mitsuishi's voice when doing Juri from Utena. I was quite surprised when I found out that Juri and Usagi were voiced by the same person. I still can't believe it really haha.
Her success in the roles of Usagi in Sailor Moon and Misato in Evangelion made her really damn prominent during the mid 90s. Then you also have the role of Excel from Excel Saga which literally injured the vocal chords of the dub actress who first tried to fill in.
Okay I see. Well I see a lot of people talking about the english version and it's been long enough I only really remember one very minor change(not dealing with Chibiusa) so maybe there's some kind of change to her character I've forgotten about? Although even in AnimeGaf I see comments about people not liking child characters.
I'd honestly never endorse watching Sailor Moon in english. It's taken enough abuse in that language.