Viking helmets are surprisingly simpler than most people realize, many of them likely just caps with a noseguard. It’s possible that metal helmets were actually rare.
Take a look at any costume store and pick out a Viking costume, and you’ll likely find a winged or horned Viking helmet—but this is actually inaccurate! Thanks, Marvel’s Thor. This idea was possibly perpetuated from the Romanticism of the 19th Century. There are only a few surviving helmet fragments, and only one reconstructed 10th century iron helmet, from Gjermundbu in Norway.