I would really appreciate some guidance if anyone has any thoughts. It seems I keep making variations of the same case. Whether it's 6u or 3u, but the result seems cramped and uninspired because I'm probably cramming too much in. I see videos of cases that are a handful of modules that seem more interesting and sound great.

Things that interest me are modulating sequencer output, clock modulation, switches, logic and lots of cv modulation. Non-generative controlled chaos if that makes sense. I have an Analog 4 for sequencing and other semi modular gear (dfam, 0cost, some other stuff with cv and cv sequencers). I'm less interested in multifunction devices with menus. I could drop the dfam into a case but it seems crude somehow haha.

Ideally, the case would provide a couple synth voices that could alternatively provide a few percussive voices. I'm not attached to any of the modules in the example below, but I do love the sound of the STO and Godspeed. The Stages clone seems versatile but maybe a maths would be more interesting.

Do you have any of these? The easiest way to get going on this and clarify your needs and demands is to just get a couple of the things you absolutely want the most and then figure it out from there. The good thing is that you already have a DFAM and a 0-Coast so you don't need a "basic signal path" to get started. You can just start picking up whatever you want to try that might add to what you already like and want from those. It's not adivisable to get it all at once - something always comes up to complicate things or necessitate a different module be swapped in. (For example, you'll either have to sub in a different low pass gate or hunt one down and likely pay way more than necessary for that LxD, since it's discontinued and sort of a cult item). Doing this gradually will give you more time to think and more trial and error period without the wasted time of selling things that don't make the cut or the overload of learning too many things at once. To me it almost sounds like you should start by experimenting with different logic modules and the like first, since that's the thing you don't currently have and seem most interested in. The oscillators and filters are probably good to have as well (especially the LPG if you want percussion that feels snappy and is easy to set up), but you can already make sounds and probably already understand that side of signal flow.

And pick bigger modules where you can. Not only will you find this cramped, but 2hp modules are just a nightmare to use in general. They work great in terms of their functions as far as I've seen but both the ones I had were tough to fit in a case. That's another issue here. All these small modules are going to create opportunities for ribbon cables and the like to make it harder to fit everything in (even if your case is more than deep enough). Some kickass modules are just small, but this exact functionality would be much easier and better if it took up roughly twice as much space (or more, but don't get too crazy).

Thank you for taking the time to reply. No I don't own any modules yet. You've given me a lot to consider. I think I am over planning without knowing what will work for me.

That's especially great advice about picking up some logic, maybe a Maths or some other modulation, and a switch as a start. Then experiment with sequencing what I already have. Ill get some good usage out of just that for quite a while until I know what my next modules will be.

Dive on in and take it slow.