Jo: Knuckles Chaotix was a title for the Sega 32X, where Knuckles and his friends Vector, Espio, Mighty and Charmy would be bound with this weird bungee-cord-ring mechanic. I never played it, and only heard about it somewhat recently.
The main "ship" is SONAMY, i.e. Sonic and Amy.
Then we have Sonic and Sally (hardcore fans)
Then we have Sonic and Shadow... Sonic and Tails, Sonic and Knuckles.
And finally, Sonic and Robotnik and, I'm not kidding.