Need an Atari trackball? Can't guarantee it'll work (it should work), but it is an Atari item. Also have a spare copy of Air Land Sea Battle if you'd like it. Free stuff, just asking for shipping
Also a WICO joystick or two (but those will cost ya as well).
I've also got an Intellivison (working) with a number of games (if you want that gen's oppposition system). Even have some of the controller overlays
This will cost you a little more than shipping (but not much more).
Email me if interested on any of this stuff.