I’ve been through a LOT of these over the years. My faves (that you didn’t already mention):
Soma Ether
LandscapeFM Stereo Field
JMT Synth LD-1/LD-2 (they have a ton of other cool boxes too)
Erica Syntrx
Korg Monotron Delay
Grendel Drone Commander (ammo box or pedal)
I recommend doing so very much indeed. I was lucky enough to find the first iteration plus expander and the custom 84hp case for a decent price, and with the addition of some utilities and Soma Lyra-FX it’s a monster.
I didn’t mention this because it isn’t highly unusual, and also it is not out yet. But the Sonic State video was pretty compelling, and I think it might do well cross-patched with some other Eurorack-compatible gear.
I haven’t tried an Ether yet, but I have tried other EMF inputs and have lots of good recordings. They are awesome when you find the ‘right’ sound. But a bit too noisy for me otherwise and I often found I found exactly the tone I was looking for, but couldn’t isolate for the other interference. Thanks.
If you don’t mind digital then Nuomo Qun mk2 can do drones, has midi, a sequencer and a 3 track looper with infinite overdubs, built in fx, sounds very nice, parameter locks, and can load samples.
The learning curve is a little steep, but fairly straightforward once it clicks, which gets easier the more you use it.
You can get some very interesting and unusual tones from it, it also has FM, great filters and can FM between samples and oscillator or what have you.
Very flexible, tiny but not the most hands on although you can control almost everything via midi CC.