I've a preliminary list of control pads I've found on my travels across the net
it's obviously unfinished
there are more here which I've prepared for but haven't copied info from yet
some beasts I've already covered. Most haven't been. However, I'm guessing that a lot of you will own third party controllers and can shed some light on the situation. e.g. what separates them from the official versions, the pros/cons, the manufacturers, names, release dates, regions etc. Better photos and box scans would be nice too.
There are also several problems regarding older controllers, specifically those for the Sega Master System. It's a well known fact that a lot of controllers are interchangable with other computers (and consoles) of the day, which could mean there's acually a lot more Master System-compatible joysticks than expected. I've spotted arcade sticks which have half a dozen leads for different consoles so things are very confusing.