Shopping Korean wigs

This shop sells wigs made by an artist Baiou, there are some styles very similar to the ones from your photo. From what I see though they are mostly limited and/or out of stock but if not straight from the shop you can try your luck second-hand.

 

Oh now that I remember, there was also one nice etsy shop that might have something similar, I'll try to find it in my history.

 

Found it! Here's one example wig that looks a lot like what you're looking for! They have more styles in their shop too.

 

This one is kind of similar and they offer black. When you click on some of their wigs they sometimes offer different colors apart from the one in the thumbnail, so try and look through all the styles you like even if they're blonde or silver or other color ^_^