Thread: Choosing a low bass oscillator
How would this fit your needs and budget?
https://www.modulargrid.net/e/takaab-vlh-vco-s-little-helper
I don't have one but it sounds like it fits your bill.
Enjoy your spare HP, don't rush to fill every last space, this is not like filling sticker books. Resist the urge to 'complete' your rack, its never complete so just relax.