Vikings are so D&D, because, you know, vikings are so metal, and metal is so D&D, and the transitive property. Hell, Basic D&D has a viking on the cover.
It’s pretty much a requirement that your campaign world have a viking culture. (To be a D&D viking you must wear horned helmets and raid in longships.) So who are the vikings in your D&D campaign? You didn’t… forget the vikings, did you? No worries! Come right this way, we’ll fix you right up.
The typical viking races
Humans: On Earth, the real vikings were all human, so humans get a big edge right off the bat. The ubiquitous human “barbarians of the frozen north” are very strong viking candidates. In fact, the 5e PHB Barbarian illustration is a human viking. In your campaign, do the barbarians of the frozen north have longships? If so, congratulations! You’re done.
Dwarves: Appearance- and culture-wise, dwarves are basically short vikings. They have beards, horned helmets, axes, and mead halls. There’s just one problem. They’re typically AFRAID OF BOATS. This is a major disadvantage for going a-viking. Maybe dwarves are just really good at facing their fear. If you can get the dwarves onto the deck of a ship, they make great vikings, of the “we’re good guys for some reason, never mind what we do on our raids” variety.
Dragonborn: Dragonborn as vikings explains a few things. 1) Why did dragonborn just appear in your campaign in 4e or 5e? (They sailed in from an offscreen Fantasy Scandinavia continent.) 1) Why do longships always have dragon prows? (Those aren’t wooden figureheads; longships are built around the mummified remains of the tribe’s draconic ancestor, and the ship itself has a breath weapon.)
Orcs: Orcs have a lot of things going for them. They love to pillage and they look good in horned helmets. Orcs are a fun enemy; they’re even more fun when 30 of them can loot an undefended village and sail away before the PCs arrive. Give the PCs the mission of defending several coastal villages. That’s right: time to split the party.
the atypical viking races
halflings: If you use halflings as your viking race, you’re really playing against type. Let’s do our best. Armored up, and wielding half-sized military forks, halflings sail their shortships into unsuspecting villages, arrive at peoples’ houses right before lunchtime, and sit around looking expectantly at the buffet table.
medusas: Beautiful armored women gallop across the sky, surveying the battlefield. They choose the mightiest mortal warriors – and turn them to stone so that they will each be immortal monuments of their own prowess. On Ragnarok, Odin casts Stone to Flesh across the earth.
sea elves: Sea elves have all of the tactical advantages of vikings – they can raid coastal communities with impunity – but they don’t need boats. Give them double axes and green elf-beards, and give them some way to keep their mead from floating away in the sea water (squeeze bottles?)
scrags: This approach is pretty similar to sea elves, except using sea trolls instead. Up till now, I’ve never had any use for scrags. But I’m amused by the idea of using a race of Grendels as the horn-helmeted, mead-swilling Beowulf clones.
wights: The word “wight” means “man” in Middle English and Germanic languages. Take that literally and you get a faction of intelligent undead warriors, sort of like the Forsaken from WoW or the White Walkers from Game of Thrones. Put them on longboats and play some heavy metal and you have a pretty badass enemy.