Autocomp attempts to generate simple bass/drum/keys accompaniment parts from chord sheets, suitable for practising with. Requires CSound.

More details:

Autocomp takes as input a text file containing chord changes, plus
time signature and bpm information, and outputs a csound .sco file
containing a simple arrangement of those changes. A sample .orc file
containing a bass instrument, a selection of keyboard instruments and
a small sample-based drumkit is provided.

The idea is not to produce music that you would want to listen to,
necessarily, but rather to produce something that you could jam along
to and practise with using a fake book.