These are keycaps - the caps that go over the switches on a keyboard:
They're custom-produced keycaps for Cherry MX mechanical keyboards (common among gaming and office mechanical keyboards).
They're produced in special batches for custom 'group buys.'
You can see the GB link for "GMK Forge" here:
https://geekhack.org/index.php?topic=101948.0It's got a number of photos. It caught my attention because the colour scheme strongly resembles Underrail's UI:
It's got that burnt-orange base, dark grey, and cream white. The white on orange is something you see specifically in some parts of the UI, like character creation.
The special axe and forge icons relate to certain melee weapons and crafting, and the general area of Foundry. In fact, you could almost call the set "GMK Foundry."
Anyway, I'm not recommending that people go out and buy these sets, as they are very expensive, but I thought it was cool. And GMK makes other retro sets based on the old monochrome monitors that inspired Underrail's UI:
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