I'm sure there were plenty more, but here are a few off the top of my head. (for the Genesis) Sega CD, Sega 32x. (for the NES) Powerglove, (for the Saturn) Twin-Stick, (for the PS2) Trance Vibrator, (for the DC) omg...so many. Maracas, Fishing Reels, Mice, Keyboards, Microphones, Cameras, etc.
None of the above got much love from developers, because of market fragmentation. The good news (for DC owners) was that those controllers allowed flawless ports of their arcade titles since you had the same controller setup...and also the Trance Vibrator is both super creepy and clearly brought to you by the same minds that created tentacle rape pr0n.