Onomastics (study of names) specialist here!

For the most part, any name you think of as "stereotypically Irish/Scottish/Scandinavian" from today, was typical during that time period, although in many cases the spelling would have been different, and the current spellings reflect changes to the sound and writing systems of those languages. Sven, Niall, Olaf, Duncan, Ragnar, Medb (Maeve), Sadb (Sive), etc. were fairly common names.

Names you would not find back then, are any variants of Christian names. Seamus, Ian, Iago, Sean, Jacques, Siobhan, Johannes, Ivan, etc. are variants of James/Jacob and John/Jack. Variants of Thomas, Peter, Simon, Mary, Margaret, and Elizabeth, would all likewise not develop until after the Christianisation of Europe.

Some less familiar names you would've found back then: Aid, Diermait, Suibne, Domnall, Loigaire, Fiachu, Ailill, Rudraige, Cathair, Toirdelbach (Ireland)

Cadfan, Einion, Rhodri, Maelgwn, Gruffydd, Hywel, Cynan, Arthfael, Pasgen, Owain, Cadwgan (Wales)

Archibald, Gillesbeag, Giric, Ciniod, Eochaid, Malcolm, Cuilen, Dub, Etgar, Alasdair, Lulach (Scotland)

Halfdan, Cnut/Canute, Gnupa, Sigfred, Harald, Valdar, Hrothgar, Hrolfr, Sigtrygg, Hemming, Eric, Leif, Frodo (Tolkien wasn't just pulling names out of his ass, most of the time!), Asa, Vikar, Saeming, Bjorn, Gandalf, Hilde, Sigurd, Heid (Germanic, especially North Germanic)

Tervel, Vinekh, Telets, Krum, Sabin, Toktu, Vladimir, Malamir, Amal, Cniva, Balamber, Octar, Bleda, Ernakh, Igor, Stanislas, Alexei, Nichita (Slavic)

Of these groups, the Slavs underwent Christianisation the earliest, a few hundred years ahead of the rest, and they also had the most ethnolinguistic groups sharing the same territory, of all the groups described here, so many of the Slavic names are from different source languages than others in the same list.

One of the shortcuts to answering your question is to look for lists of rulers from those regions, from that time. It is very much a trend in all parts of Europe, for rulers to give their children "conventional" or locally popular, conservative names... and it's a trend as well for people to name their children after their monarchs. As such, the names of rulers tend to be very common names, either because popularity inspired that choice of name, or because that name because popular by being a monarch's name.

Admittedly, women's names are not nearly as well conserved. Mythic histories feature a lot of women as characters, but those names aren't as reliably common. Ireland does a better job than pretty much anywhere else, at keeping track of women's names, mostly because sovereignty could pass through maternal lines and marriage to a sovereign woman, not just paternally from father to son. Plenty of stories depict solitary woman rulers, and the same general rule of "monarch names become common names" applies for women as much as for men. This is why Maeve, in particular, has survived so well.

I hope this adequately answers your question; cheers!