The original Sega Genesis unit came with one controller and the Altered Beast game.
This is a picture of the Sega Genesis outfitted with the 32X, a Power Base Converter (allows Master System games to be played), a 6 button joystick, and the 3 button control pad.
The XBand Modem.
An advertisment for a Genesis.
The portable Sega Genesis - "Sega Nomad".
Power Base Converter