RGBY is Asia/EU/Oceania.
RGBY (along with the greys and purple of the console)
is on the Super Advance arcade-style joystick controller which was a NA release for the SNES and while not made by Nintendo, it was an officially licensed product they had outsourced. Nintendo themselves then released a variation of the SA in Europe called The Score Master which also used RGBY colors on it.
Then there are a couple variations of the handheld controllers which used RGBY were both again licensed and released in NA. One was made by ASCii (same people that made the Super Advanced) and High Frequency. [Note: another controller was officially released, but I can't remember who makes it, but was called The Super Joy Card though not available in NA). If memory serves me correct, both NA handhelds were functionally the same, though aesthetically different as the ASCii had horizontal switches, while the HF had vertical.


I own a Super Advance along with 2 High Frequency Turbo controllers. SNES is still my favorite system with my favorite game of all time as well: A Link to the Past.
Edit: ASCii also made a one-handed version for the non-NA market, but I can't remember what it's called.