BuyFromEU

I see, you work in IT

I can recomend www.falke.com and www.schiesser.com. Falke is a bit more expensive. For Standard I prefer Schiesser (5 pairs for 20 EUR)

There's also Ukrainian https://dodosocks.com/en/holovna/

Edit: Noticed you asked for thigh high socks. These manufacturers probably don't have any but I'll leave the comment up in case someone else finds it useful.

If you're asking for dress socks or something in that direction there are tons of brands.

On the "budget but quality" end I recommend Viccel although they're from Turkey so not strictly EU.

https://www.viccelshop.com/about/

On the more expensive end of the spectrum there is:

https://www.bresciani.it/en

https://meschaussettesrouges.com/en

Then there's Bexley, a cheap French store that used to sell shoes online and has since then expanded into other areas as well. Products weren't necessarily top quality but they had a few notable shoe models that became popular for being decently priced/made back in the day. If you need "normally" priced socks that are over the calf they have them. They are made in China though so not exactly what we're here for, but given the company is European maybe it's an option if nothing else works out.

https://www.bexley.com/

And lastly there's Suitsupply from the Netherlands (socks made in Italy). They at least sometimes sell over-the-calf socks but their socks and products in general were never really good quality and they've gone down hill from there over the years. They are cheap though and made in Europe so I thought I'd mention them too.

https://suitsupply.com/

Hope you find what you're looking for!

https://www.varusteleka.com/en/category/socks/2171?s=5

Some of these are made in Finland. I can recommend the light merino wool socks. The non-light are quite thick so if you want something for cold weathers, they work well.

They tend to shrink a bit even if you wash them correctly in low temperatures. My shoe size is 42, but the 43-45 size socks work well for me.

Suva is an Estonian company manufacturing all kinds and lengths of socks, both wintery options and summery in all colours. Brief check said that delivery to Netherlands is fixed €11 so bulk will be cheaper. Suva leggings have been my winter staple for years and the socks I have from them have lasted for years as well.

From France, I love Loom! https://www.loom.fr/collections/chaussettes-hommes

They're a bit expensive but in my experience they actually manage to design clothes that hold for long. I think they actually do some durability tests and try to optimise based on it.

@Goldholz

Socks made in France:

https://www.marques-de-france.fr/chaussettes-made-in-france/

https://www.varusteleka.com/en/product/varusteleka-knee-socks-merino-wool-4-pack/79180?option=35717

These are my go-to's. They aren't thigh-highs, but are pretty tall.

And there's a sale on!

I don't know about European manufactured, but the kind of socks your describing - normal black socks, without a seam - in Germany are called "Kellner socken" - waiter socks. Light, seamless, comfy usually black tie socks, not too expensive.

From any European fashion brand? Though most of them are made in South East Asia and not in Europe.

From https://lemmy.blahaj.zone/post/23575279, https://www.trigema.de/en/men/accessories/Sports-Socks-Twin-Pack-black-35-38.html

You could checkout brands on https://www.grundstoff.net/ or https://www.avocadostore.de/ . If you are adventurous experiment with wiljd socks (wearing them right now): https://www.wijld.com/

https://sopuli.xyz/comment/15463552