Gleamball hunting / searching: What is the process?

No, that information isn’t available on Boundlexx. Biome info effectively isn’t visible anywhere I’m aware of after world creation unless the owner posts it.

Also, note that the color info on Boundlexx is gathered/updated when someone running the scanner (BoundlessProxyUI - Help track Sovereign World Colors + More!) looks into a portal of a world. This means that color data can be quite out of date, especially if the portal is obscure or non-existent.

My wife and I run Chromis I, which has a public monthly survey to decide the colors on the world.

While that process takes quite a bit of time, you could consider just doing it for gleam.

I would use Boundless Information Station to find some gleam colors you like that don’t have known planets (click the color name to see worlds with the color. Also, double check in the gleamhub as well, since some don’t get scan updates) and do a survey of what unavailable colors people would be interested in.

Unrelated, it occurs to me I should probably start scanning gleamhub worlds as part of my Chromis I color survey process to make things easier on myself.