Love this question. I work with fermentation research, so any kind of weird fermented anything is 100% my jam.
I was super impressed with all the options when I visited Latvia. There they have something called black balsam ( Melnais balzams), which is a 90-proof distilled bitter herbal concoction. It has valerian and wormwood, among other things, so it’s the perfect nightcap.
Another thing I tried in Latvia was this birch sap wine, which I really want to find again! It had these amazing but subtle herbal grassy flavours. And because it uses indigenous yeast to ferment, it tasted quite funky, like a Spanish Sidra. That was a truly unforgettable and unique experience.