I'm getting into Tidal Cycles, which is a live coding midi sequencer platform. Many of the tutorials just describe using a single port midi interface so it can be difficult to understand what is the code and what is a variable if you are just starting out.
If you have more multitimbral synths and sound modules than you have multiport midi outs for, then you might use a midi patch bay.
Ever since the chiptune music genre became a thing in the mid 2000s may independent developers have been creating software and hardware that either emulate vintage video game sound chips, use old stock sound chip in new synths, or even use the original game system hardware and building out sound chip triggering features. These would essentially turn a video game system into a midi controllable synthesizer in the form of custom carts and/or controller inputs. At Deep Signal Studios we have called a number of systems such as:
A lot of vintage synth, sampler, drum machine, and sequencer owners are discovering that it is possible to replace floppy drives with floppy drive emulators. They come in a few different version, being HxC and Gotek. HxC came along first and had developed a more commercial business model and Gotek is the cheaper alternative that is supported by a few open source projects for the DIYer. These are new devices that connect to the floppy drive ribbon cable and host a USB flash drive or SD card which can contain hundreds of disk image files.
RTP-MIDI, AppleMIDI or MIDI over Real Time Protocol is a way to send midi over a network in real time. Most of the time it is used to send midi within a local network to either hardware or software instruments but it can also be used to send midi over the internet. However, the timing is not always perfect. In my experiments, connecting to over the internet back to another local computer I experienced occasional lags, which got worse as I visited new web addresses that were data heavy like a YouTube video, but the lag went away a few seconds after the video got started.