The Elder Scrolls 5: Skyrim is a vast open world, and as such, there's a lot of monsters to be encountered over the course of the game. The same can be said of Dungeons & Dragons, which pretty much boasts the ultimate list of monsters, since it's so long-running and varried.
Most monsters in games and other media have roots in common folk tales and myths from around the world, and as such, share characteristics even if they aren't the same "thing." So, we compared the monsters of Skyrim with the monsters of Dungeons & Dragons, and came up with a list of monsters that are basically each others' equivalent--if not always in name.
Atronachs
Atronachs are a lesser species of Daedra, each formed from their own element of power; there are flame, frost, and storm atronachs. As such, the atronach most resembles an elemental from the Dungeons & Dragons catalog of monsters, as elementals, too, are beings made from their elements of power--though there are more types of elemental than atronach, as elementals can be fire, water, air, earth, in addition to a whole host of lesser elements.
Atronachs generally resemble humanoids made entirely of their element wearing loose pieces of armor (save for storm atronachs, which have a more indistinct form), and can be encountered either as enemies or summoned allies. Elementals are similar, save that each elemental type occupies its own plane--meaning that there's a plane of fire, water, etc.
Draugr
Draugr are undead Nordic warriors of old, doomed to guard Skyrim's crypts and Dragon Priests forevermore. The more "advanced" draugr even know dragon Shouts, and draugr as a whole are the most common enemy when crawling through a tomb. Due to their undead status and appearance as an emaciated long-dead humanoid, they most-resemble zombies in Dungeons & Dragons monster lore. Those, too, are animated corpses, though zombies are generally made by a necromantic spell of some kind performed on a corpse, and zombies are utterly mindless, bent completely to their maker's will. In addition, any kind of solid creature can be turning into a zombie, not just humanoids.
Dragons
Naturally, dragons are on this list. The main villain of Skyrim is the fearsome dragon Alduin, while the other is literally called Dungeons & Dragons. It's in the name.
In both franchises, dragons have similar appearances and attitudes; that sense of superiority over humanoid races is seemingly universal, though that's unsurprising for a race of gigantic intelligent flying lizardlike creatures. The main differences are in the types of dragons and their respective "civilizations." In Skyrim, dragons are presumed extinct until the return of Alduin, who possesses the power to resurrect his kin. In D&D, dragons are very much alive, though generally solitary and isolated in their existence, with more good-aligned metallic races and generally evil chromatic races.
Dremora
While Dremora also fall under the "Daedra" category, they more closely resemble devils in Dungeons & Dragons. They serve the daedric prince Mehrunes Dagon, and like devils, they have a very orderly militaristic society with many ranks and subdivisions within dremora clans. Intelligent and capable of human speech, dremora are typically powerful warriors, but can also be formidable spellcasters in same cases, also similarly to D&D devils.
Dwemer
Skyrim's version of dwarves are called the dwemer, and they've got an altogether more sinister history than Dungeons & Dragons' dwarves. In D&D, dwarves are one of the more common and classic playable races, and they look pretty much like one would expect a dwarf to look. In Skyrim, the it's a mystery what the dwemer looked like, but they were actually cousins of the other elf species, including bosmer, dumner, and altmer. Not only that, but the dwemer are responsible for the creation of the falmer and the destruction of the snow elf race, having tricked and collectively blinded them centuries ago. Now believed extinct, all that remains of the dwemer are their perilous and technologically advanced ruins.
Falmer
In their original snow elf form, falmer would of course be comparative to the elves of D&D, of which there are many subraces. However, for different reasons, the falmer's D&D equivalent is actually just one specific subrace of elf: the drow. Now, in appearance, the two couldn't be more different. Drow elves are black-skinned and much more "human"-looking, while the twisted falmer are much more animalistic in appearance and pale as can be. It could even be said that falmer are a more realistic example of what underground creatures would evolve into, since they're cut off from sunlight in all forms and live in the damp darkness of caves and ruins.
Their similarities lie in the fact that both, as outcasts but technically counted as elves, live underground and are unerringly hostile to creatures of the surface world. When proceeding underground in Skyrim, players are likely to be fighting falmer. When doing the same in D&D, it's usually to battle the drow.
Giants
Both Skyrim and Dungeons & Dragons have creatures called giants, and while they're both exceedingly tall and generally hostile, that's about where the similarities end. Skyrim giants are barely capable of communication with people, while giants in D&D range based on their subtypes from a similar state to quite intelligent with a complex society; they merely choose not to contact humans, feeling a similar sense of superiority that dragons do.
Hagravens
Hagravens are evil creatures sometimes encountered in a relatively small western area of Skyrim's enormous map. According to legend, they used to be human witches who traded their humanity for the ability to become a hagraven. In D&D, therefore, the adjascent creature would be an actual hag; in D&D, hags are fey creatures with origins in the Feywild who frequently live in covens of three, and there's a broad variety that includes sea hags, green hags, night hags, and bheurs. While they were isolated covens, Skyrim hagravens are usually found commanding groups of Forsworn.
The Elder Scrolls 5: Skyrim is available now.