To use on a computer, you can output raw MIDI serial data, then use Hairless MIDI to convert the serial data to MIDI and playback on a MIDI device of your choice. Here's and example using the Virtual MIDI piano keyboard.
And here's an example of Bluetooth MIDI
And you can also program with Bluetooth MIDI in Swift
The GM 1 sound set defines a set of common instruments:
Keywords for search: control a MIDI instrument from the micro:bit, Does the micro:bit support MIDI