Some mistakenly believe that MIDI files have poor sound quality. However MIDI files don't have any sound, they aren't audio recordings. Instead they contain event lists, instructions for virtual instruments, things like when notes are to be played and released. The best analogy is piano rolls: before records were popular, the wealthy had player pianos. These not-computers were able to "read" a roll of paper with holes in it, and mechanically activate the corresponding keys.
EQ used MIDI to play audio samples in a sound card’s ROM, which, depending on your hardware, could be augmented with files in the EQ directory like synthusr.sf2. For perspective, I create MIDI files whenever I record my piano performances, but the program I use for playback, Synthogy’s Ivory II Grand Steinway, contains over 27 gigabytes of audio samples, just for the piano.
These are the 422 EQ MIDI files (including redundancies) that someone extracted from the XMI files in the EQ directory and posted on the EQ forums a few years ago. They're Jay Barbeau’s performances, and not cleanly synched to measures like sheet music.
If you can load soundfont files, these are from the EQ directory:
synthusr.sf2 was for Original and Velious, synthus2.sf2 was for Luclin