I shared this article on the history of dragons in Western literature on Facebook, and there was a comment about how Oz wasn’t represented in it. It does, however, quote Ruth Berman, a long-time Oz fan; and I think she’s written about dragons in the Oz books and related works before. The article mentions how dragons weren’t used a whole lot in nineteenth-century fantasy, perhaps because of the Satanic connections (although there is always the Jabberwock in Through the Looking-Glass), but the end of the century brought works like Edith Nesbit’s Book of Dragons and Kenneth Grahame’s The Reluctant Dragon, which included dragons who clearly weren’t evil, and could be friendly and funny. J.R.R. Tolkien would later bring back dragons who are quite nasty, but also clever. I think L. Frank Baum’s use of dragons fits into the time period, as he also tends to make them figures of fun.
The Purple Dragon in The Magical Monarch of Mo is a villain, but more ravenous and mischievous than strictly evil. He mostly eats crops, and at one point bites off the King’s head. He also has silly physical traits, being able to stretch like rubber and having raspberry jelly in place of blood. The Enchanted Island of Yew has a dragon who’s old and rather ineffectual, It looks terrifying, being more than thirty feet long with diamonds on its scales and legs as thick as that of an elephant. He has rheumatism from the dampness of his cave, is unable to gnash his teeth because King Terribus had them carved into various shapes, has had his fire put out by a strong wind, and is paranoid about meeting St. George, who might have killed his father (the dragon just says his father “got into trouble with Saint George,” so it’s not clear). The Dragonettes in Dorothy and the Wizard in Oz have their tails tied to rocks to keep them out of trouble while their mother is away, so once again they can’t do much of anything, and they’re very haughty about their pedigree.
Tin Woodman has a young dragon being scolded for wanting to eat between meals.
Quox in Tik-Tok is much more formidable than some of these others, being incredibly strong, able to breathe fire with no problem, and undamaged when the Nomes throw spears at him.
He’s quite friendly, though, and the humor with the character comes in with his being a rebellious teenager who doesn’t respect his elders. He comes from a land where dragons are treated with respect, suggesting more of an Eastern than Western view of the mythical animals. Erma, the Queen of Light, explains that some of the Original Dragon’s children “wandered into other lands, where men, not understanding them, made war upon them.”
Ruth Plumly Thompson’s take on dragons was somewhat different, in that they’re more often antagonistic, but not necessarily any more serious as threats. It’s more like her characters are the sort of people Erma mentioned who don’t understand them. Royal Book has a dragon who’s a pet of the Grand Gheewizard, and like the one in Yew, is old and has rheumatism. Sir Hokus of Pokes, who is anxious to prove himself by slaying a dragon, kills this one even though it isn’t doing anyone any harm. Much the same is the case with Enorma in Grampa, who has false teeth and dies when submerged in a stream. She can still hunt, however, and is dangerous to the people of Isa Poso, who are made of ice and snow and melt when she comes near.
Quiberon in Giant Horse is a meaner sort, but he doesn’t harm any of his caretakers, whom he needs to polish his scales, comb his hair, sweep out his cave, and tell him stories.
He threatens to destroy the Ozure Isles unless he receives a mortal girl to attend him, however, and the Wizard of Oz turns him to stone despite his soft side.
Dismocolese in The Enchanted Island of Oz is generally harmless, serving as the gatekeeper to the Kingdom of Somewhere, but he does try to eat David Perry despite being on a diet of raw beef and greens. He is, however, afraid of water.
While not written as an Oz story, “A Story About Dragons” (later “The Dragon of Pumperdink”) presumably takes place in the same Pumperdink that’s later revealed to be in Oz, and he takes a job as the castle furnace during a harsh winter.
John R. Neill also brought some friendly dragons into the series, Evangeline being the most prominent one.