Masterpieces for Marimba by Thomas McMillan is a collection of short Baroque pieces transcribed for marimba, all playable with two mallets. These pieces were originally written for the flute or violin, but fit idiomatically on the marimba very well.
This collection of short solos gives today's percussionists a healthy dose of classical literature so they get the same musical education as instruments that have a far longer history in Western classical music! Composers represented include Telemann, Mozart, Corelli, Handel, and Bach.
This text is a good resource for solo and sight-reading material.