As you guys know I have been a lurker for a while and have just started building my library, is there any 6 button controller option for the Turbografx?
Hey welcome, for TG officially, no.
You have to get an Avenue Pad 6 (or others such as Commander PC controller) and a converter cable to use it on your TG-16.
Good luck!
Just confirming what MotherGunner said.
You can also take a pce tap and the cable out of a turbo controller, make a modification and use it as a converter. There are instructions if you search