A Ukrainian ethnic subgroup, which makes up the third group of Carpathian highlanders in addition to the Hutsuls and Lemkos, is the Boykos. My grandfather was born in the Boyko region of the Carpathians, though his parents were from the Sambir and Lviv regions. Like the Hutsuls and Lemkos, the Boykos have a distinct culture, largely stemmed from their isolation in the mountains and highlander ways. But like all the different Ukrainian cultures, dialects, and traditions, the Boyko culture is slowly disappearing.
Here’s a good article about the Boykos in English.