OnePlus actually has six different modem SKU's of the OnePlus 8 depending on your region and carrier. One SKU for the unlocked North American model, one for T-Mobile, one for Verizon (with mmWave support), one for the EU, one for China and one for India.

The 8 Pro has four modem SKU's as it will not be sold through carriers. This is compared to two or three for most other manufacturers.

Colors are specific to the storage options and regions on the OnePlus 8 and 8 Pro.

The Glacial Green color is available only on the 8 GB RAM/128 GB storage versions of the 8 and 8 Pro in the US and is available only on the 12/256 GB versions of the 8 and 8 Pro in the UK. It is available on the 8/128 and 12/256 versions on the 8 but only on the 12/256 version of the Pro in the EU. India and China get this color in 8/128 and 12/256 options on both phones.

The Interstellar Glow color is available only on the 12 GB RAM/256 GB storage version of the 8. This color is not available in the UK and China.

The Onyx Black color is available only on the 12GB RAM/256 GB storage version of the 8 Pro in the US. It is available on the 8/128 and 12/256 variants in India and China for both phones. This color is only available on the 8/128 version of the 8 and 8 Pro in the UK and the EU and is not available on the 8 in the US.

The Ultramarine Blue color is only available on the 12GB RAM/256 GB storage variant of the OnePlus 8 Pro. It is not available in the UK and China.

Edit: Seems like colors and storage options are region specific as well 😂. Updated the colors as and how we've seen it in various markets.

There's a pointless animation when you click on the OnePlus 8 and 8 Pro links on their website.
8: https://www.oneplus.com/8
8 Pro: https://www.oneplus.com/8-pro?from=head

With a JNCD of 0.4 you can see accurate colors on a OnePlus 8 Pro.

This is the best display in the industry.
With green tint on a $1000 phone.