For ambient music, as a second oscillator in addition to the versatile Plaits you can perhaps start with a double oscillator and a waveshaper
A serious cheap option
https://www.modulargrid.net/e/noise-reap-paradox-- (oscillator)
https://www.modulargrid.net/e/modulaire-maritime-tarot (waveshaper).
They are the ones I have in mind for my next case extension.
-- ferranadsr
The Noise Reap paradox is fantastic. And the latest version has some great additions (which make the module a little more crowded). I'm using the v1 in my rack and it's already very versatile.
The Machine: https://www.modulargrid.net/e/racks/view/1601144