In my game, goblins are green or yellow-green.
I also have "Red Goblins" which are tougher and meaner, and gristly. (Expect to see them in "Ye Olde Schoole Module", for release sometime this year). Red goblins have rust-red or red-brown or brick red skin.
In my Oathbound campaign, I've renamed the Red Goblins "Moggs" from the Magic the Gathering games. These are taller than typical goblins, uglier, and meaner. But in game terms they are identical to my red goblins.
I've also got "Keepers" in my Oathbound game, who are bright red Moggs (who have fire immunity).