I have been collecting and building my Eurorack Synth for several years now and it has grown a lot since it's first form.
So far my Eurorack spans across three different cases and I have a 4th sitting empty at home for when I finally cave and make another purchase.
I use a Zoom F8 as the final output of the synth to the speakers and the recorder for the Synth. The F8 is great because I can utilize the sub and main outputs of it in creative ways.
I actually can send my synth into the F8 channel 1 and 2, send them to the main out and use it to record them. Then I can send a phantom powered microphone into the F8 Channel 3, then route Channel 3 out the sub out rather than the main out. I can then patch the sub out into my synth via Phonogene, Mikrophonie or any other input module and mess around with that signal. This is great because when I hit record on the F8 I can capture the output of the synth (effected mic signal) and the dry microphone signal at the same time. This can be extremely helpful when doing sound design.
Besides my Eurorack I also have a Teenage Engineering OP-1 which I love to run through the Eurorack as well.
Here are a few videos I made using my Eurorack for Sound Design: