You can get RGB LEDs that look like a regular LED but contain a red, a green, and a blue LED in one. The individual LEDs tend to be extra-small to allow all three to fit in a regular LED. These RGB LEDs allow you to emit any of the three colors or three combinations or white (and even more colors by adjusting the amounts of the three primaries). However, even though the RGB LEDs are supposed to be a single component, the fact is that they contain three separate LEDs which of course, are not in the same place. You can see their separate positions by casting their light on something close to it.
I don’t think there are any “true” RGB LEDs. There do exist LEDs that are true yellow, orange, purple, cyan, etc. and emit an actual wavelength of that color rather than combining additive-primaries, but they are static and can’t be adjusted to different wavelengths. That’s probably not even possible. YouTuber StyroPyro has lasers of different wavelengths like yellow or cyan. There are even, variable-wavelength lasers.
