Clouds is out of production, so unless you have one on hand or want to go thru sourcing a used one, you're better off using a third-party build. These also tend to be considerably smaller, which is also useful. The Peaks is in the same situation, btw.
If you have this paired with a 2s, you might want to look into some modules which can screw around with timing, particularly if you want to get better use out of the Euclidean Circles. Logic modules are a must for manipulating gate behavior, plus adding some clock dividers/multipliers would also probably prove useful.
Buffered mult: unnecessary. If you have 4-5 VCOs to drive with a single CV, you'd need it. I advocate using NO multiple modules on small builds like this, btw; you can get the job done with inline mults and/or stackcables and save some panel space.
Add another VCO. Even if you're using something like Plaits as VCO 1, having a second VCO to detune or sync against it will yield some excellent (and bigger-sounding) results. This also means you'd need to add a proper mono mixer to combine your VCO outs, and after that you might consider a CVable waveshaper (Tiptop's is a good choice) to get more timbral variety. Plus, add a quantizer; yes, the 2s has that, but one with various scalar patterns might come in handy to get some cross-modal lines going against the 2s.
Have you considered adding effects, such as delay, reverb? Again, this is something that really fattens up/complicates your sound, letting you get more out of what's here.
Lastly, add some modulation sources such as envelope generators and LFOs. The Maths is useful, but you need more of this sort of thing, potentially along with a couple more linear, DC-coupled VCAs for manipulating CVs and modulation signals. Perhaps some attenuverters would go well here, too, for some nuanced control over your modulation.
Not too bad a start, otherwise. But it's got a ways to go. Try and keep things small when populating a cab this small. And also, watch your module depths, as the Rackbrutes really only have about 40mm in practicality.