add-on  list  of  15  instruments :

Top of the list ,
in authentic tonal
reproduction :

Vibraphone
World Flutes
Electric piano
Electric Bass
Upright  Bass**
String Ensemble
Concert Guitar
Vintage Organ**
END

honerable mention :

Space Pad
World Percussion**
END

with careful blending ,
these instruments can be useful :

Pop Brass**
Saxophonia**
Orchestral Ensemble**
END

instruments you might not need :

Century Guitar**
Grand Piano**
END

notes** :

Upright Bass        ; No  Bow .  finger playing only
Vintage Organ       ; uses Lots of Voices , needs Lots of CPU .  3 Ghz or faster
World Percussion    ; is good , with a somewhat limited niche
Pop Brass           ; high notes might play Trumpets , low notes might play  Trombones ( sections only , No  solo )
Saxophonia          ; solo Tenor sax
Orchestral Ensemble ; is complex . high notes might play Flutes , middle notes might play Violins , low notes might play Tuba
Century Guitar      ; is some kind of electric guitar ( not sure what the cliche' sound is )
Grand Piano         ; is kind of a  repeat ,...another piano