In the Netherlands… I have experience with https://www.homegreen.nl and I can recommend their cultures (From them I have bought Lion’s Mane and King Stropharia).

I have bought Cordyceps off Etsy sellers, but unfortunately I can’t strongly any of them, because I have had really underwhelming fruits that looked like what one would expect from and old / sub-cultured strain.

In the Netherlands we have a website to report different species found in the wild. For Cordyceps militaris I can see that October is the most common month to find them (https://waarneming.nl/species/16371/statistics/), and in the map I can see the areas in which they are most commonly found: https://waarneming.nl/species/16371/maps/?start_date=2023-04-12&interval=15552000&end_date=2023-10-09&map_type=grid10k

So I am planning to go to a few hunting trips these coming weekends and hopefully I can find one in the wild… If I am not able to establish a wild culture, I think I will order from a vendor in the US, as there are a few Cordyceps breeders with a good reputation there. But i will keep an eye on this post in case anyone can recommend an EU Cordyceps vendor.