tbh once you unlock a new biome, there's very little reason to go back to any of the previous biomes, so why not bump up the value of the lower-level biomes by adding BO, biome-exclusive NCL eye colors. They can only be unlocked when your king is at Impressive or higher and you're in the right biome for the eye colors to generate. With these requirements met, NCLs will have a low chance of spawning these biome exclusives! For now, I'll only add one color per biome, but if enough people request it, I can propose more colors! I'll add visual looks later once I figure out out to get a template for my eye ideas

Temperate Savannah
Seedbud

A light green color ringed with pale yellow, the name reflects both the color and the fact that it's in the first biome a king will explore in.
Pass colors: Seedbud, Green, Olive, Jade, Yellow, Cucumber

Shrubland
Woody
Light brown gradient with pale speckles & a bright yellow shine; the speckles and yellow evoke the shrubs of its biome during dry season
Pass colors: Woody, Brown, Bronze, Yellow, Earth

Tropical Forest
Viridian
Fairly dark teal, fading to bright green, it evokes the similar vivid greenery of the rainforest.
Pass colors: Viridian, Green, Aqua, Crystal, Emerald

Dry Savannah
Baobab
Ruddy copper with a creamy white iris. It matches the color of the fresh-but-aging flowers of some baobab species.
Pass colors: Baobab, White, Brown, Cognac, Sinoper

Rocky Hills
Igneous
A dramatic gradient from dark bluish gray to silver. It's like they're made of shards of volcanic rock.
Pass rate: Igneous, Silver, Black, Jet, Gray

Arid Desert
Sandstorm
Very light, peachy-golden color that fades to almost white. A lot of desert animals share the same coloration
Pass rate: Sandstorm, Peach, Sunstone, Tan, Yellow

Marshlands
Saltwater
A central gradient from rich greenish blue to a paler, warmer tone towards the pupil. The marshlands are likely connected to saltwater, maybe some of that color leached into their eyes :)
Pass rate: Saltwater, Seafoam, Aqua, Sapphire, White

Waterhole
Vibrant
A mottled gradient, gold to blue, speckled with lighter colors to resemble the reflection of the sun on water. The waterhole is busy with animals, so it's only reasonable that its exclusive eye color is as rich in color as it is in wildlife.
Pass rate: Vibrant, Amber, Blue, Crystal, Sunset

If anyone can show me an empty template for the explore eye previewer that would be great!