Some interesting older (pre-1990) scores that I feel are well worth investigating. Most of these are in print, or fairly easy to find...
Irving Berlin: MISS LIBERTY & MR. PRESIDENT
Noel Coward: SAIL AWAY & GIRL WHO CAME TO SUPPER
Sammy Fain & EY Harburg: FLAHOOLEY
Cole Porter: OUT OF THIS WORLD and SILK STOCKINGS
Rodgers & Hammerstein: ALLEGRO & PIPE DREAM
Arthur Schwartz: A TREE GROWS IN BROOKLYN & THE GAY LIFE
Lerner & Loewe: PAINT YOUR WAGON
Harold Arlen: ST LOUIS WOMAN & HOUSE OF FLOWERS
Dubey & Karr: HAPPY HUNTING
Bob Merrill: TAKE ME ALONG & HENRY SWEET HENRY
Hugh Martin: BEST FOOT FORWARD & HIGH SPIRITS
Bock & Harnick: FIORELLO & THE APPLE TREE
Kander & Ebb: WOMAN OF THE YEAR & STEEL PIER
Jerry Herman: DEAR WORLD & MACK AND MABEL
Jule Styne: SUBWAYS ARE FOR SLEEPING & DO RE MI
Shire & Maltby: BABY & CLOSER THAN EVER (revue)
Sherman Bros: OVER HERE
Krieger & Lorick: THE TAP DANCE KID
Stephen Schwarts: THE BAKER'S WIFE
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com