Are you talking about the old Radio Shack chips?
AY-5-8116 Dual Baud Rate Generator (#276-1792)
AY-3-1350 Melody Synthesizer (#276-1781)
SP0256-017 & SPR016-117 Voice Synthesizer (#276-1782)
They were made by General Instrument.
Yea I have a couple XR2206s in my bag of tricks, the ICL8038 was a nice one and I'm aware of the Max038 but even that one is out of production. It seems like the function generator IC market is dead.