Pretty self explanatory. For me, and it seems to be a common one among the community as a whole, purple seems to be pretty popular. I'm not entirely sure why it is but it is the one I've seen a lot of.

I'd also go with purple, or any variation of it. Usually, I'll prefer to see a variation leaning towards the bluish spectrum of the color. I must say, however but I've never quite been sure of whether or not it is a common one among the community as a whole. Can you show me some examples of what you have found to be some?

Purple. I think the reason is the majority of manips and art I saw with glowing eyes (especially back when I first started, especially especially higher effort ones) used purple. And since the only thing I saw as much as glowing purple eyes was spirals that were sometimes two shades of purple, sometimes black and white, and the black and white ones usually looked less well done (again, at the start of me looking at pics online)...

TL;DR: I associate it with purple because when I started it featured the most in well made stuff that'd stay in my memory.

"Honorable" mentions:
Green, which tended to be reserved to aliens and ghosts mostly.
Pink, which a few artists I like tend to use.
Yellow, because same.
Light blue, because it's a nice color that was generally used with more soothing stuff, which I like.

black and white

This is a very subjective question, but I'll give my very subjective answer:

For me, any color that conveys a sense of "otherness" or "difference", as well as artificiality, is a good color. This means one that contrasts with the scene, and ideally doesn't really complement it either (according to complementary color theory) but still compelling (forming a 2nd point of a triad with the predominant color, with the third part of the triad conspicuously missing, for example). For "artificiality", inappropriate hues and high saturations - for example, [[medrifogmatio]]'s characters have skin colors that are simply... not actual skin colors, by any stretch, and this arguably enhances the sense that their minds are strange.

Bold purple is a common go-to because it's 1. not a natural person color, 2. high-saturation, and 3. when applied to eyes or skin, doesn't give the same impressions of nausea or jaundice that going in the yellow-green direction might.

That said, there's lots of other options:
- Specifically because it doesn't seem like a body tone, a greener color can work when trying to emphasize <<hypnohub.net/post/show/10...tomless-brown_eyes-brown_|an external force>> upon the subject.
- <<hypnohub.net/post/show/38...tinggirl_-manipper-family|Pink>> is arguably the most feminine color, and combined with a high saturation is a safe go-to for non-drone femsub.
- Multiple colors. <<hypnohub.net/post/show/41...ir-cegi_-cegi93-coils-com|a cohesive palette>> implies serenity, <<hypnohub.net/post/show/19...ny_-jay_naylor-black_hair|jarring contrasts>> imply disorientation. You're not limited to kaa eyes (see <<hypnohub.net/post/show/14...ter-blonde_hair-bodysuit-|here>> and <<hypnohub.net/post/show/10...-dazed-edgeofthemoon_-man|here>>.)
- If the scene is already bright and colorful, you can get contrast by going the complete opposite route and having the control be low-saturation or even <<hypnohub.net/post/show/19...meltoe-cell_phone-change-|monochrome>>. This is mostly appropriate for "blanking out" types of control (as opposed to e.g. bimboization).

Finally, there's absolutely no hard-and-fast rules, and I have images I like as well as images I've created that are in violation of all of the above - these are just general guidelines that tend to work well.

-Purple: good all purpose mind control that works regardless of what's going on, but particularly good with psychic or magic
-Pink: good for heart-eyes, glow typically implies love or lust
-Red: brighter reds would go towards pink and the heart associations, while darker or combined with Black work for corruption or villainous ends (I associated Red lights with machines typically)
-Green: bright Green goes with unnatural things and corruption, especially paired with Black, while more earthy tones can be used for plants, Fey, or magic
-Blue: more ethereal and ghostly to me, but is also a good tech-control color in light or a screen
-White: implies blankness or void, while combing with Black creates a classic spiral indicative of simple trance
-Black: rarely works well on its own, but accents other colors very well as a secondary
-Yellow: I'd call it more of a plant color in darker shades, for pollen or drugs

Just my thoughts.

Brown & Black !