Dwarves appear in a number of forms in myth, legend, and fiction. However, there is little true variation between their appearances in fiction. Most modern depictions are heavily influenced by Tolkien—stout, strong, sturdy, immune to cold and fire, stubborn, persistent, brave, proud miners, metalworkers, and stone carvers. Many even hate or distrust elves, though Tolkien’s originally befriended elves, until the War of the Jewels.
Because of Tolkien’s influence, most modern dwarves have their roots in the Norse svartalfar. These beings were skilled artificers who rarely interacted with mortals and dealt almost exclusively with the gods. Perhaps one reason is that they turn to stone in sunlight. There are few, if any, real descriptions, but greed and miserliness seem common in the myths. Most accounts that describe them talk of bearded old men, but the Poetic Edda mentions women (the only source that does). The svartalfar created most of the notable artifacts of the Norse gods.
The Tolkien-style dwarf is common throughout the fantasy genre, though rarely as a focal character. There are some exceptions, notably some of the TSR/WotC novels and Markus Heitz’s The Dwarves. They are virtually unheard of in urban fantasy. Ilona Andrews briefly mentions some in the Kate Daniels series. A few are met, and one mentors the protagonist, in Rick Riordan’s Magnus Chase series. And one appears in Eoin Colfer’s Artemis Fowl series, as a thief who is able to eat his way through dirt. This could be very interesting ground for some variations and adaptations.
Steven Brust creates the Serioli, who create Morganti weapons, as an insular and unknown culture and society. They live alone in the mountains and don’t interact with outsiders except to trade for their magical weapons.
RPGs introduced distinct varieties from mountain to hill, deep to grey, and even the infamous gully dwarves. They also introduce the idea of dwarves being non-magical. Warhammer and many video games give dwarves gunpowder, often. Still RPGs and video games limit dwarves to mountain dwelling of hills (surface or under) with little, if any, variation. This lack of variation can, perhaps, be laid at the feet of the FRPG introduction of gnomes as magic wielding cousins to dwarves.
Elves & Fae
Despite their reputation for being clichéd, there are actually a fairly wide variety of depictions of elves, and fae, out there. While most takes show elves as beings of good, there are several examples of spins that display them as evil, racist, capricious, cruel, manipulative, and vindictive. Some of these also focus on an elven/fae boredom and interest in games (ex. Terry Pratchett’s Discworld and Holly Black’s Tithe trilogy).
One of the primary sources of fantasy elves is the alfar of the Norse. These residents of Alfheim are governed by the Vanir, in some myths. They are beautiful, ambivalent toward mortals, and often worshipped as gods themselves. Some tales, later ones, suggest that they were vulnerable to Christian artifacts.
The other major source is the Celtic Sidhe. These fairies and spirits dwelled in barrow in Gaelic mythology. They possessed various powers, most oriented on combat effectiveness or nature/beasts. Some tales depict them as personifications of the Irish gods.
Tolkien’s version has influenced modern interpretations most heavily. His elves were the same size as Men, but stronger and immortal/unaging. They were the lords of natural spaces and possessed great power, though Tolkien did not explicitly state what they were capable of (just that the average Nazgul feared the power of Elflords). They appear to lack the need for sleep and are depicted as a purely good species.
This led to the “traditional” fantasy depiction. Many fantasy elves are woodland residents, just under human to human height. They are strong, slender, and agile beings with a strong affinity for magic. Unlike humans and other species, they tend to favor bows and speedy weapons rather than brute force. They typically display a distaste or hatred for dwarves and orcs, while being friendly or at least neutral to humans. They are often depicted as being condescending toward “lesser” races, but are good in nature.
One semi-deviation from the “norm” is Steven Brust’s Dragaerans. Dragaerans name themselves “human” but the Easterners (humans) often refer to them as elves. They are tall, strong, muscular beings able to access powerful magic via the Orb. Virtually all are racist toward Easterners. They are also related to some degree to the various beasts of the world (those of the Great Houses, at least). Most are urban dwellers, except the Teckla.
J.K. Rowling’s House Elves are both a deviation from the “norm” and a hearkening to the old folklore. As little folk who are bound to service to wizards, these spindly elves evoke the brownies and domovoi of European folklore. They, like their taller, noble cousins possess powerful magic, but they are subservient and limited in when they can use their powers.
Giants are, as their name suggests, tall humanoids that appear throughout myth, folklore, and the fantasy/urban fantasy genres. They often show up as mere muscle or a threat to the characters. Usually, they are uncivilized and sometimes man-eaters (folklore). That said, they have been incorporated into urban fantasy (Rowling, Riordan), though part-giants are much easier to conceal for a hidden magic world. Often in fantasy they appear as little more than war machines or wilderness threats.
Perhaps the most well-known mythological giants are the jotun of the Norse. These giants come in a variety of sizes, but all are taller than humans whether slightly so or the size of mountains. There are two major varieties: the fire giants of Muspelheim and the frost giants of Jotunheim. All Norse giants are strong, tough, and enemies of the Aesir. Some are excellent illusionists and shapeshifters, including Loki.
According to Geoffrey of Monmouth, the last Welsh giant was Gogmagog. This creature was defeated by a companion of Brutus of Troy in Albion, causing the land to be named Cornwall in his honor.
Among the Greeks, giants were children of Gaia (Hesiod) and enemies of the Olympian gods. They are variously shown as humanoid or having snakes for legs. They appear in Hesiod, Homer, Pindar, and Alcman. These giants possessed great size and strength, being the size of mountains, and represented excesses and hubris.
Tolkien briefly discussed giants. His giants are massive beings of stone that throw rocks at each other and wrestle during a storm in the mountains near Rivendell (The Hobbit). There is minimal description, oddly for Tolkien, in this scene.
Rowling’s giants are primitive, massive, violent humanoids. They are capable of mating with humans, rarely. They are tribal in society, favoring strength over intellect. They are also a dying species, reduced to remote mountain lands due to human expansion and resulting habitat loss. They often side with dark wizards in the magical community’s conflicts.
George R.R. Martin presents giants beyond the Wall. These are powerfully strong, huge humanoids who only live in the North. They are presumably a dying species, but readers only see a handful, including Wun Wun. Even so, Martin provides relatively little description of the giants and their society.