I see no developer took interest in filling the demand as of yet, but since this is the only thread on the subject I came across, I figured I'll drop a list. They're not viking/pegan voices, but they just might fit the role pretty well. Or at least some of their patches and articulations. I recommend looking up some library walkthroughs/reviews on them.
Cinesamples - Voices of War, Men of The North (Male)
Impact Soundworks - Vocalisa (Female)
Strezov Sampling - Rhodope II (Female)
Silence+Other Sounds - Omen (Male and female)
Wavelet Audio - Groth (Male and female)
Zero-G - Ethera Gold 2.5 (male and female solos) also their Ethera Gold Sahara Voices (female), although this one is highly subjective. Still, I'd say it's worth a look.
I want to add Best Service - Dark Era for Engine 2 (doesn't work in Kontakt), but the content is incredibly dated. And worth of the few vocal patches found there which may be of use will depend on the track you want to make. Still - worth a look, but carefully consider if a few not so great male throat singing patches and dealing with yet another launcher is worth the price.
Some patches in Balkan Ethnic Orchestra might be of interest as well.
On a side-note, I saw a few people mentioning authenticity of 'viking music'. My two cents - for the most part it's purely speculative, the only (relatively) sure thing we know about it are the instruments used, although even this topic has plenty of grey areas. One can learn a lot about what their music must have been like just from understanding the culture and studying those instruments. They were simple, the concept of practicing for hours every day to become an accomplished musician didn't exist. So naturally their melodies and songs themselves must have been simple, and since writing a song structure with the same intent behind it as music nowadays wasn't a concept either (ie; grip as large an audience as possible with either a fancy performance or a clever play on melodies), I imagine it was extremely limited and dare I say - boring. We like to romanticize the ever elusive and lost to us music of ancient cultures, forgetting that with our musical standards engraved into our brains so deeply, if we were to finally hear it in it's original iteration, more often than not we'd be rather disappointed.
But none of that is actually relevant, is it? I sure love the artistic interpretation of it from various modern artists, and I'm more than satisfied with what we got. I prefer to enjoy it and play into it, rather than concern myself with it's accuracy. As we'll fail to capture it either way.
