These dice are so beautiful, but I don't know what company makes them. Does anyone know what company made these dice?
This is a set of 7 Elvish dice by Q Workshop. You can see them here on Paizo's store, specifically transparent and black. This is probably an old, out-of-manufacture set: Q Workshop now stocks a different set of Elvish dice with a different font for the numbers, so they probably updated their Elvish dice product line with new designs. Paizo might be the only place to get them since the other dice shops I could find are only stocking the newer version.
I'm confident it's this exact set since we can compare the 12 face on the d12:
On the left is Paizo's d12 from my image above, on the right is the d12 in the bottom left of your image rotated 180° for our convenience. You can see how the font face and all the sigils surrounding the d12 line up perfectly.
We can also check that the d4 has the numbers positioned on the edges rather than the points, a common point of difference between dice sets. (In the photo at the top of my post, we're seeing a flat face of the d4, with the point facing away from us, but the light shining through from the point makes it look a bit like we're seeing it point-on.)
How I found this
There's a number of manufacturers who make or sell super-decorative polyhedral dice sets like this. I couldn't remember the usual suspects but a google search for "fancy polyhedral dice" turned several of them up — Awesomedice, Diceshop, Q Workshop, DnDdice, and Alchemist's dice. I quickly went through their polyhedral set inventories, found no exact match, but kept seeing Q Workshop's newer Elvish dice set.
That avenue wasn't going to give me anything, but I had a new lead. These dice do look pretty Elvish, so I went to Google Images, searched "translucent polyhedral elvish dice", and sifted through the results. A result that showed the same designs in a different color took me back to Paizo's store. Their broader collection of other colors in this design included our suspect. Hooray!
I thought it might've been Paizo's own branded product at first, then I noticed the Q Watermark in their product images.