The ES-8 is somewhat the heart of my setup, and more lately with the ES-6 expansion am I able to take full advantage of the variety of outputs offered in that 424mkIII 4track. I also use it as an interface to work with VCV Rack, like in using that hardware sequencer to control VCV voices.
I happen to have a littleBits synth kit and found that, with the addition of an audio input module, it works quite well as a dynamic effects unit, particularly with something like that microcassette dictaphone.
I also have an old graphic EQ which I discovered has the ability to pipe through dry and wet signals, allowing me to shape the 424’s stereo mix a bit more while simultaneously preserving it before committing both simultaneously to the digital realm, alongside each of the four discrete unmixed tracks, all simultaneously.
Overall, it’s a pretty boring setup, as my eurorack (yawnorack) lacks any voice of its own, at the moment (besides the two sample outputs on that sequencer). But it’s served as an excellent bridge between the worlds of analog and digital, which was sorely lacking in my repertoire before its assembly.