CMF2IMF converts Creative Labs' CMF music files into id Software's IMF format. It can create both type-0 and type-1 IMF files, and supports any IMF speed (so it will work with Commander Keen, Wolfenstein and even Duke Nukem II.)
MID2CMF converts type-0 MIDI files into Creative Music Format (.cmf) files. CMF files use MIDI data internally, but like MOD files they contain custom instruments (in this case OPL instruments as opposed to MOD's sampled instruments.)
DRO2IMF converts DOSBox Raw OPL captures (.dro files) into id Software Music Format (.imf) files, which are used for storing background music in many Apogee games (Commander Keen, Wolfenstein 3D, Monster Bash, etc.)
DRO2MIDI converts DOSBox Raw OPL captures (.dro files) into MIDI files. It also converts id Software IMF and Rdos RAW captures. It's based on Guenter Nagler's IMF2MIDI program, but with many enhancements (OPL rhythm-mode instruments and pitch bends are now converted.)