To explain why this is needed. AI can already do heterochromia, but it can't tell left and right aside. Because of how perspectives work, observer's left is a character's right. I experimented a lot with trying to give a character heterochromia, but color placement was pretty much random. Even using the same prompt gives different results. Sometimes you can just mirror the image to flip eyes around, but that only works on symmetrical characters.

This model is trained on characters with heterochromia and character's right eye being red (left for observer). It removes that uncertainty.

A second attempt at heterochromia preset, more specialized one. Since the previous one barely worked, this one is just for having red right eye with green, purple or blue left one.

During training, this one produced MUCH more consistent results, but there were a couple right green eyes with red left ones, but not on the last iteration...

On testing, other colors work too, just replace the color for left eye in the prompt.

Red and Blue: red_right_eye_heterochromia, heterochromia with red right eye and blue left eye, red eye (right eye), blue eye (left eye)

Red and Green: red_right_eye_heterochromia, heterochromia with red right eye and green left eye, red eye (right eye), green eye (left eye)

Red and Purple: red_right_eye_heterochromia, heterochromia with red right eye and purple left eye, red eye (right eye), purple eye (left eye)