Anthem MIDI Sequencer: A feature packed, easy to use MIDI sequencing package.
MelIDI: Advanced MIDI and Audio sequencer.
MidiWorks Sequencer: Professional MIDI Sequencer now free for download
Monolith: Freeware MIDI music playback module for RISC OS. Includes a desktop front end.
ReMIDI: Freeware program that will play MIDI files without the need for buying extra hardware. By Michael-Dennis Biemans.
RISC OS abcMIDI: Abc notation is a simple but powerful ASCII musical notation format.