Norse mythology had a system of characters. As far as I believe, things we know about creatures in Norse mythology are just the tip of an iceberg. The rest of the story might be burned in the power of time and dust. But whatever it could be, to master the things we have today demands an amount of time and effort, let alone the whole Norse myth.
Creatures in Norse mythology
Aesir gods and goddesses: Aesir was the main god tribe in Norse mythology. The Aesir lived up in the highest branches of Yggdrasil Tree of Life. The Aesir chief god was Odin the Allfather who was always willing to sacrifice his things to gain more knowledge. Odin once traded one of his eye for knowledge. Below Odin were many other powerful gods like Thor Viking God of Thunder and Storm, Baldur the Viking God of Light and beauty, Frigg the Viking Aesir chief goddess Odin’s wife, Tyr Viking God of Honor and Fairness, Heimdall the powerful Asgard Watchman, and so on.
Vanir gods and goddesses: the Vanir god tribe located up in the Vanaheim. But where exactly Vanaheim was located remains a mystery. The most famous Vanir gods and goddesses were Njodr, Freya, and Freyr. Njord fathered the twin Freya and Freyr. Njord was the seafaring god, Freya was goddess of war, and Freyr was god of sunshine and summer.
Giants or the Jotun: The giants in Norse mythology were much associated with darkness, evil, forest, and death. The giants were the enemies of the Aesir god tribe. Loki lived with gods in Asgard but he was actually a giant from Jotunheim land of the giant. Some famous giants in Norse mythology include: Hel the queen of the underworld, Skadi giant of snow, hunting , and skiing, Jormungand Midgard Serpent, Fenrir Wolf of Destruction, Nidhogg the dragon wants Yggdrasil to collapse, and so on.
Elves: Beautiful but not always kind to the people. They sometimes helped people out of the trouble but sometimes they wanted to cause humans a great deal of hardships.
Dwarves: In Norse mythology, dwarves were the most skillful craftsmen. They created many treasures for the gods: Mjolnir hammer for Thor, Gungnir spear for Odin, etc.
Valkyries: the female helping spirits of Norse gods, espeically Oddi. The Valkyries helped to fly out other worlds to observe and pick the most powerful and bravest Viking warriors.
Norns: Viking Norns were powerful creatures. They were supposed to weave the fate threads of other people’s life.
Humans: Humans in Norse mythology were not different from us in this day and age.