Allegory is a literary device in which characters, settings, and events are symbolic of something else outside the story. If we think of Fantasy as escapist literature then allegory doesn't seem to quite fit with its goal of transporting readers away from humdrum lives to experience the wonderful and magical. Allegorical Fantasy can still do this, but it will ultimately present a message the brings readers back to the real world. We all read to experience something fresh and new and exciting and magical, but at the end of the story we must go back to our lives. Allegorical Fantasy deliberately gives readers something to take back with them. Keep in mind that allegory is different from you finding meaning in a story—it is authorial intent at its finest.
Variable. Magic is not a defining characteristic of Allegorical Fantasy so writers have complete freedom to develop, or not, systems of magic. Even when magic is part of the world, it is often a symbol of something else outside of the story—magic as a symbol of power, magic as innocence, magic as greed, and so on.
High. This sub-genre is all about ideas. Allegory by definition is the representation of ideas and concepts. Morality, philosophy, theology, all inspire topics for allegory. Allegorical will make you put your thinking cap on. Just in case you don't like hats, you will still understand the literal meaning of the story and hopefully still experience of the joy of reading—but you'll still be missing out.
Low. In a true allegory, characters are not three dimensional, they are symbols meant to represent some idea (often a moral quality). Characters are often used to develop the details of the allegory, which means they are not individuals. But! The really good writers will be able to make their Allegorical Fantasy more than just a lesson. They will be able to create characters who are symbolic and multi-dimensional. Characters who have motivations aside from advancing the allegory. When writers succeed at building more complex characters the ultimate lesson is all the more powerful because readers will be invested in the symbols that reveal meaning.
Variable. The events of the plot will contribute to the development of the allegory and further enhance the story's meaning. In this sense, what happens in the story isn't nearly as important as the symbolic meaning of the events.
Variable. The level of violence is going to depend on the message the story is ultimately trying to convey. A story about protecting the beauties of the natural world is not going to be as violent as a story that inspires people to throw off the yoke of servitude.
High Fantasy High and Epic tales of the Fantasy genre almost always include quest. Many use High and Epic fantasy interchangeably, though there are some differences between the two. One can include the other.
Quest Fantasy Epic Fantasy almost always features some quest goal.
Coming of Age Fantasy Many epic fantasy tales (but not always) might feature the coming of age tale of a young man. Wheel of Time for example, A Game of Thrones, A Sword of Shannara, etc.
Sword and Sorcery Crossing Sword and Sorcery with Epic Fantasy makes for an action-packed quest.
Heroic Fantasy The hero or heroes, of Heroic Fantasy often embark on a quest.
Mythic Fantasy and Legend Retelling Fantasy. Mythology, folklore, and legends are filled with quests. In these tales the quest is as much a plot device as it is a symbol.
By C.S. Lewis. A classic high fantasy series with much adventure to offer. But, it can also be read allegorical and incorporates Christian imagery.
By Richard Adams. On one level a classic tale of adventure, with anthropomorphized rabbit characters. On another level, it is an epic struggle between tyranny and freedom.
By George Orwell. A satire of socialism and communism told through a group of farm animals who revolt.
By Brian Jacques. A massive series about medieval rodents. Martin the Warrior is a recurring figure in the series, even though it spans generations. Martin can be seen as a mouse Christ figure.
By George MacDonald. This is a children's book about a boy who travels with the North Wind. But, it is also brings out many philosophical and spiritual questions.
By Kenneth Grahame. Another story about anthropomorphized animals. This is an affectionate tale about adventure, friendship, and realization.
By Paulo Coelho. Santiago is a shepherd boy who embarks on a physical and spiritual journey. It is a story about innocence and wonder and finding meaning in life.
By Norton Juster. A children's book about a boy who is really bored and finds himself playing with a magic tollbooth where he discovers that learning is fun.
By Edmund Spenser. A collection of tales about a magical land full of knights and monsters and beautiful maidens. The tales are an allegory about virtures and also include some political allegory.
By J.R.R Tolkien. Strictly speaking, LOTR is not allegory. Tolkien specifically indicates his distaste for allegorical tales. However, his assertion has not stopped many readers and scholars from reading the trilogy allegorically and finding meaning for themselves—this makes LOTR a great example of how even when authors do not intend to write allegory, readers still search for its meaning.