Seven collections/pieces - never used, mild to moderate shelf wear.  

Vivaldi: 2 Arias, for medium/low voice (IMC)
DeFalla: 3 Songs for voice & piano, original key (IMC)
Wagner: 5 Songs for high voice (G Schirmer)
Richard Strauss: 5 Songs, Op. 15 for Middle Voice (Simrock)
Johann Strauss: Songbook (Weinberger)
Beethoven: Samtliche Lieder, Book 3 (Henle)
Carl Bohm: Still as the Night