I'd just say that you'd be surprised how far you can get with just one oscillator or sound source, split the audio off 2-3 ways into different effects or through a Wavefolder etc. I'd suggest any VCO with multiple outs or the MakeNoise STO with its S-Gate will practically let you do a melody line with a baseline all out of the same module.
Options for utilities would be MI's Links & Kinks, the latter has a noise source in the S&H section.
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.