Take and discard whatever you want from this thread, it's mostly to inspire.
Creatures of Hjaalmarch

Very few dare to enter unprepared into the wet landscape of Hjaalmarch. This creature hides itself in the murky swamps, camouflaging itself in the mist as it waits for a careless adventurer to stick its foot into the water. Many children in the town of Hjalvyk have in recent years gone missing, which the villagers have suspected this creature to be responsible for. (based of Nøkken, a swamp-creature that lured people into the swamp to drown)
More swampy pictures:





Witches of Skyrim

The townspeople of Hsariik are a superstitious kind. Rumours of plague-bearing witches has made the nords afraid to walk outside at night. The witches are defined by their dark hoods and their old rakes. In reality, these types of witches rarely leave their huts in Mount Anthor. (This is a personification of the black death, called Pesta, that took the lives of at least half of the Norwegian population)
More of Pesta





Snow monster

This mountain creature only attacks when provoked. It can be difficult to see these docile creatures during the winter, as their white fur blends in the snow. Although mammoths and bears are preferred, certain Nords will travel up the mountain to hunt them down for their pelts. Hunters and bandits sometimes wear the white fur as camouflage.
Sea Draugr

The rocky shores of Haafingar suffers from a very unique type of Draugr; the sea draugr. These undead creatures are believed to have been ancient nords, drowned in the cold and dark waters around the Sea of Ghosts. They have a more bloated appearance compared to their more common cousins, and are covered in seaweed. Adventures who have been lucky enough to survive will never forget their stench, a mix between fish and rotten flesh. (I understand that draugr are embalmed undead creatures that protects tombs, so this sub-creature doesn't exactly fit into TES lore. However there is such a thing as Sea Draugar in Scandinavian culture, so I'd love to see this kind of creature in Skyrim)
More Sea Draugr



White Hold

Fog is common in the sparse tundra of the Whiterun hold. The mountainous landscape around the tundra can be seen in almost any direction.
Snow Whale Mirage

At the highest peaks of Skyrim, the songs of the snow-whales can be heard echoing against the mountain walls. Very few in recent times have seen a snow-whale, and imperial scholars have concluded that they might have never existed at all. But Nords are still stubbornly talking tall tales of the whale-songs, and their mirage-like appearances in the mountain clouds.
Sea Serpents

Rumour has it that giant sea serpents lurks in the depths of the Sea of Ghost, attacking any adventuring ship that would ever try to travel north to Atmora. The only evidence of these creatures ever existing are the giant teeth that sometimes can be found at the shores of Dawnstar hold. Paintings and murals of sea serpents hangs in many houses in the city of Dawnstar.
Example of sea serpent paintings



Giants

The Nords in Falkreath hold have many encounters of stray giants. These giants will traverse through the dense forest in search for food. It is common practise to paint food in swirly and colourful patterns to be left for the giants to take. In recent years the giants have become more aggressive, which has lead to the fighter's guild having to control their population. (Based of the Norwegian troll)
More trolls




Dire Wolf

Wolves are a common predator in the more fertile areas of Skyrim. They usually hunt in packs, but it isn't uncommon to see the much bigger variant “dire wolves” hunting alone in the dark forests. Imperial scholars believe that the rumours of werewolves stems from dire wolf encounters.
Other inspiration of Dire Wolf - Fenrir

Across the fjords with boat

Boats are a common transportation through the wast fjords of eastern Skyrim. It is one of the safest ways to travel from Whiterun to Windhelm, as long as no bandits ambushes you from the shore.
Across the mountains with horse

The horsesleds through the mountains is a much more dangerous way of transportation. Very few wants to weigh the risk of the sled getting stuck in the snow, becoming prey to bandits or worse.
More snowy art


