Here is a list of all pieces in The Works project that are for one or more string instrument soloists (other than violin only) with orchestra. The list is arranged roughly chronologically.
If the work doesn't have a title beyond “X Concerto” or “Concerto for X and Orchestra”, then only the composer's name is mentioned (see Walton under viola for an example). If the composer has more than one such concerto, the number or numbers are listed (see Haydn under cello for an example).
The list under each instrument heading is organized roughly chronologically.
Viola
G.P. Telemann: Concerto, TWV 51:G9
Hector Berlioz: Harold en Italie
William Walton
Paul Hindemith: Der Schwanendreher; Trauermusik
Bela Bartok
Luciano Berio: Chemins 2; Chemins 3
Morton Feldman: The Viola in My Life IV
Cello
Antonio Vivaldi: Concerti, R. 413, 424
C.P.E. Bach: Concerto, H. 439
Luigi Boccherini: Concerti, G. 476, 479, 480, 482, 483
F.J. Haydn: Nos. 1-2
Robert Schumann
Camille Saint-Saens: No. 1
P.I. Tchaikovsky: Variations on a Rococo Theme
Antonin Dvorak
Richard Strauss: Don Quixote
Edward Elgar
Ernst Bloch: Schelomo
Frank Bridge: Oration
Paul Hindemith
William Walton
Dmitri Shostakovich: No. 1
Benjamin Britten: Symphony for Cello and Orchestra
Gyorgy Ligeti
Witold Lutoslawski
Henri Dutilleux: Tout un monde lointain…
John Tavener: The Protecting Veil
Peter Maxwell Davies: Strathclyde Concerto No. 2
Double Bass
Peter Maxwell Davies: Strathclyde Concerto No. 7
Harp
G.F. Handel: Concerto, Op. 4 No. 6
Claude Debussy: Danse sacree et danse profane
Alberto Ginastera
Luciano Berio: Chemins 1
Mandolin
Antonio Vivaldi: Concerto, R. 425
Guitar
Antonio Vivaldi: Concerto, R. 93 (guitar or lute)
Joachim Rodrigo: Concierto de Aranjuez; Fantasia para un gentilhombre
Heitor Villa-Lobos
Luciano Berio: Chemins 5
Multiple String Instruments
W.A. Mozart: Sinfonia Concertante, K. 364 (violin and viola)
Johannes Brahms: Double Concerto (violin and cello)
Michael Tippett: Triple Concerto (violin, viola, and cello)
Peter Maxwell Davies: Strathclyde Concerto No. 5 (violin and viola)