I feel like this would had been better to present as a base made of a single colour with only one colour channel.
The only reason I mention this is because anybody could take the full red, blue or green ones and easily hue-shift it or use channel mixer in GIMP for a good result. But otherwise, a good effort.
The white on black one is a good example of how channel mixer could come in handy, since it cannot be hue-shifted, but channeled down to a specific colour, or be colourized (i.e. made to use a single, different colour without channel mixer). I guess black on white could be inverted, hue-shifted to the opposite of the colour one is after then inverted again for the end result.