Roland GS
Roland's 1991 extension of General MIDI, adding extra sound banks, more drum kits and controllable effects.
General MIDI promised 128 instruments and not much else. Roland wanted to sell more than that and launched GS alongside the Sound Canvas SC-55 module. GS uses bank select messages to reach variations of each base sound, defines additional drum kits, and makes per-channel reverb and chorus sends available through ordinary controllers. Deeper editing of filters and envelopes is done with NRPN and SysEx.
Because the SC-55 became the default module for PC games in the early 1990s, a great deal of game music was written for its exact timbres. The software synth bundled with Windows still uses a Roland sound set, which is why a MIDI file on an ordinary PC sounds like 1993.