Here are some quick links to repertoire lists for collaborative piano auditions at a few schools:
New England Conservatory
A few selections keep on showing up on many of these lists, specifically the Beethoven violin and cello sonatas and the Brahms violin, cello, and clarinet sonatas. The song lists differ more widely, but usually include German (Schubert, Schumann, or Brahms) and French (Faure or Debussy).
What do you think should be required for auditions for programs in collaborative piano? Should the requirements be comprehensive, as in the Eastman and CIM rep lists, or should they be simpler?