@Zzzach - Yes I got my BIM/BAM from Big City Music!
Valhalla DSP reverbs are the best I’ve heard and only 50 bones each (different verbs for different flavours). It actually sounds better than my Empress did and it’s a fraction of the cost. I know we’re talking hardware here probably, but Valhalla is really special.
Do you think their holding off on Boum because of the success of Analog Heat?
No. It’s been in the works for years, but Denis (aka Mr. OTO) wasn’t happy with the initial prototype and went back to the drawing board. I’m guessing he’s a bit of a perfectionist 
Blue sky owner. Very very very much in love
If you have an iPad there are many nice reverbs, like Crystalline or AUFX Space.
The Mooer Ocean Machine looks/sounds interesting. https://www.youtube.com/watch?v=wEpYJrGDi8E
My mate works in a guitar store and tells me he expects to sell them at about £200! I think for what you get, is a great deal.
All of the above plus…
RE-20 or a RE-201 if you can afford it.
Alternatively, I think the Boss SE-70 is a great expansion for the Op-1. I use mine for my Sub 37 and I use the SE-70’s little bro - the SE-50 - for my Op-1. If I saw another SE-70 I’d buy it straight away. The plate reverb goes upto 60seconds fyi 
This years gearlust list =
Reverb - OTO Bam
Delay - Space Case TE01 (hopefully pick it up in NYC and save on shipping)
Analog Heat
Kiss goodbye to the best part of 2k there lol
One more vote for the Space reverb here. Expensive, yes but so very deep.
So 101 question, I could trigger samples from the op-1 into a reverb unit and record back into the op-1?
Yes
Seems your decision has been made but I can only give a +1 to Oto Bam. I never have to think about reverb again with this box.
It’s a delay, but i will give a try on the red panda particle. Looks crazy
Cathedral. lots of cool effects and reasonably priced. lots of used options
Have a listen to these pedals from Earthquaker devices.
This is a delay, but you can get some reverb fx going on.
https://m.youtube.com/watch?v=sJB7A48A3-0
Delay and reverb.
https://m.youtube.com/watch?v=1-edx1_Vn4g
wow these Bam pieces look amazing!
my contribution is pretty funny and maybe awful… but i sometimes just use the reverb on my marshall practice amp or the reverb on my mixing board, or computer, but for sure an expensive option would sound really good and give you amazing possibilities.
I think that would create feedback unfortunately you can only use it as a Master effect. (I know there some sort of technique around this but I haven’t tried itl).
I bought a TC Electronic T2 Trinity reverb a couple of weeks ago to go with the Sub 37. Has stereo ins/outs, small footprint, to my ears it sounds great (especially for the price; 130-150 eur), works with PSU or battery, etc. Some say it’s too ‘VST’, I say it’s digital and just delivers what it promises to. Not a Big Sky (have one, will never sell), has its limitations, but then again, it comes at the fraction of price.
(on a sidenote: the OTO BAM is a darned good unit… some day, some day…)