So from what I understand, the reason the contact colors exist in the Oasis is that for a while there was a strong objection to adding purple eyes for realism reasons. While that was understandable at the beginning from what I've heard, the "realism" ship has sailed long ago with bases like Interstellar and Pulsar existing and being seen as highly desirable. There are even passable purple eyes now such as Amethyst and Tyrian.

So what I propose is that Lavendar, Violet and Indigo eyes be given a % chance of passing themselves in addition to the colors they currently do. This would make them applicators available through the Oasis. Alternatively, the contacts could be removed from the Oasis and they would become breed-only eyes like Dawn and Starshine.

And yes, I would also like this to be extended to everyone's favorite unholy neon terror, Green. While intended as a joke, some of us out there *cough*me*cough* actually quite like the look. As this suggestion is for doing away with cosmetic/unpassable traits, I'd like to see it able to pass like other Golden Medium Solid Special bases in addition to the fails it already produces.

A few points for the "green bases must never even touch my sensitive eyeskin" crowd-
1. Special bases need a parent with the base to pass, all you'd need to do to not get bright green cubs is not breed to a Green stud.
2. The green mane was released and it passes like any other mane color.
3. It would already be nerfed by being both being a Special a Medium base.
4. If that's still too much, appeasement measures could be taken, such as a Kimanjano or Mandarin-tier droprate, only passing through Green x Green breedings, or only passable in April.

TL;DR: Because of the colorbomb Special eyes and bases out now, keeping certain old traits cosmetic and unpassable is weird.