Warden is my favorite class in the game as they are really the only class with actual in game lore. (Spoiler: it has nothing to do with Morrowind)
While it's not a lot, there's a lot of connections we can make with it's small Lore Snippet:
"Wardens are defenders of the Green, master storytellers whose nature tales become magical reality. They wield frost spells against enemies and summon animals to aid them."
Y'ffre the Singer, the Storyteller, God of Song and Forest, and Spirit of the Now, is the most important deity of the Bosmeri pantheon, also worshipped by the Bretons, and Snow Elves. Y'ffre essentially created the Green and the Green Pact with the Bosmer, to allow them to shape the trees of Valenwood to build their homes.
As with Y'ffre, Wardens are also Story Tellers and Defenders of the Green, but when we look at the different skill trees we see how much Wardens are intertwined with the Lore of Y'ffre.
Starting with the Bosmer, who are tied to the Animal Companion Tree due to a little something called the Wild Hunt, described as Described as "a flood of horrific beasts, tentacled toads, insects of armor and spine, gelatinous serpents, vaporous beings with the face of gods, blind in fury," or "a pack of shifting forest-demons and animal-gods, thousands strong, which sweeps through the countryside killing everything in its path."
Personally I wish we got some more Wild Hunt-esque Abilities over the Morrowind inspired abilities we have now. Instead of a Bird, a Viper Strike would be awesome.
Next we have the Bretons, the Bretons worship Y'ffre as the god of Songs and "the Now", and is responsible for the Laws of Nature. The Wyrd Sister's especially revere Y'ffre as the God of Nature which is another aspect of Wardens, Nature's Embrace. You could also see the Bosmer Connected to Natures Embrace as the Green Pact provided the Bosmer with the Forest Changing to their needs.
Last we have the more interesting of the two, the Snow Elves of the Merethic Era, the Winter's Embrace is connected to this aspect of Lore but, really the Snow Elves were named such as a connection to the location rather than any special Frost related Abilities. Nonetheless, we have all three followers of Y'ffre connected to all three Class Trees so there's that.
Also, lil snippet is the Khajiit who have a little lore where Y'ffre was chosen by Nirni over Hircine and Hircine got upset, sooooo. Wardens shouldn't be able to be Werewolves, because Hircine hates us.
Last Snippet is connected to the Argonians that left the hist to follow Y'ffre, but they were all hunted down by Shadow Scales because of the whole Blasphemy bit against the Hist.