The Super Game Boy 2 is the successor to the Super Game Boy. It features very few enhancements and very little is actually known about it. It was only officially released in Japan on January 30, 1998.
In terms of features it was very similar to the function of the original Super Game Boy, 5 extra backgrounds added to the list that could be displayed while playing a game, and a game link port. Outside of the aformentioned differences it was essentially the same as its predecessor.