Pokemon Red and Blue
Pokemon Ruby (Red) and Sapphire (Blue)
Pokemon Fire Red and Leaf Green
Pokemon Diamond (Light Blue) and Pearl (Light Red)
Pokemon X (Blue) and Y (Red)
Pokemon OmegaRuby (Red) and AlphaSapphire (Blue)
And now we're getting Pokemon Sun, which is red, and Moon, which is blue.
This weird obsession with red and blue color-schemes is getting extremely old. We get it. Move on.