The amazing thing is that one guy is behind everything you see and hear. Dr Pigeon is like a polymath. He develops and runs the site, creates all the sounds and plays all the instruments (with a few exceptions). I beg everyone who uses that site to donate, so he can keep going.
While this may not be the thing you're looking for, it is easy to create your own noise with VCV Rack. You can record noise that you like and transfer it to your device of choice, completely free.
It is also a very powerful music production tool but it is lightweight and fairly easy to use for noise.
VCV rack is awesome, if not the easiest to start from scratch with. For those who haven't heard of it, it's basically a virtual modular analog synthesizer. You can build your own sound generating machines out of a huge selection of modules, including oscillators, filters, sequencers, etc. Some of the modules are based on real hardware modules that you can buy, but there's a huge variety.
It's fun to play around with, but if you're new to modular synthesis then I recommend limiting your module selection to just the built-in ones to start because the full selection is pretty overwhelming if you don't know a VFO from an ADSR evelope generator.