The Quickshot Aviator 2 is one of the best. Unlike a lot the crap that was designed for the NES, this controller is original and fun to use. As you can see, it's meant to simulate a flight yoke for flying games like Top Gun (although it's interesting to use with games like Mario Bros.). It even includes an altimeter that actually works.

The Aviator 2 takes up both controller ports for your NES but it has a switch to move between first and second player. It also includes both rapid fire and slow motion setting and has suction cups on the bottom to keep it from moving.

Thanks to Pat Mc. for scans and information