I listed some classical works I like.
Konzertstuck in F minor - by Weber
Paride ed Elena - by Gluck
Sinfonia Concertante for Violin, Viola and Orchestra E-flat major, K. 364 - by Mozart
String Quintets Nos. 1-6 - by Mozart
Trio for Violin, Viola and Cello in E flat major, K. 563 - by Mozart