The Lion King (1994; The highest grossing of the canon unadjusted for inflation)*
The Nightmare Before Christmas was supposed to come before it in the animated canon, but let's just say there was an overreaction to its dark content, and this one wound up replacing it as Disney's 32nd as a direct result.
The Gremlins: (Based on Roald Dahl's book. Questions of whether plane sabotaging creatures could be made sympathetic and development running late into the war leading to a cancellation due to possibly becoming dated. Some Gremlins would later appear in the 2010 video game Epic Mickey.)
My Peoples (Loose Applachian set adaptation of The Canterville Ghost, cancelled due to the closure of the Florida studio, which was the only one making the movie)
Fantasia 2006 (due to shifting management; several shorts were completed and released separately)
Mort (Disney couldn't get the adaptation rights, which were sold as one large package rather than individually)
Sequels were also planned for films such as The Jungle Book and Bambi during earlier phases, though didn't get past early production stages (allegedly due to Walt not being a fan of sequels). Actual follow ups were made much later on, though are not made part of Disney canon.
All-Star Cast: Although not as blatantly advertized and abused as Dreamworks Animation, the movies in the canon will occasionally have a staggering roster of a-list celebrities lending their vocal talent. Before 1992's Aladdin introduced Robin Williams as the Genie, Disney preferred actual voice actors. After that, they started to increasingly advertise celebrity roles. Some of the more blatant examples; Mandy Moore and Zachary Levi as the leads in Tangled, Miley Cyrus in Bolt (particularly egregious because she replaced a voice actor who had already recorded most of her lines) and perhaps Mel Gibson.
There is severe controversy about the Kimba claim, but there is evidence suggesting the screenwriters were originally adapting it before executives decided they'd claim no connection between anime and movie whatsoever.
Animated Musical: Most of the movies in the Canon are this, though there are exceptions such as Tarzan and Lilo & Stitch.
Cover Version: DisneyMania, for a number of hits from movie soundtracks. In some cases, song covers are included in DVD sets. It's also fairly common for a contemporary artist to cover a song from a movie.
Denser and Wackier: The tone of the films constantly vary, the majority of films made in the 1960s and early 1970s use a much more offbeat and wacky tone than usual however, with less drama and more comedic and sympathetic villains. The Rescuers began the return to more darker and earnest story telling (albeit with Disney's usual whimsy).
Earn Your Happy Ending: At least eight different characters in the animated canon have had to fall from grace, hard, and crawl their way to victory. Here's a list so far:
None of the villains in Pinocchioare ever punished — Pinocchio just escapes from them. The loss of just one boy presumably not being significant, it can even be said that the Coachman won as far as his scheme went.
Knight of Cerebus: Though some may still be somewhat comedic, a lot of villains have a very menacing tone (especially in the earliest examples) and are responsible for a lot of Mood Whiplash away from Disney's usual whimsy. See Nightmare Fuel.Disney for their rather haunting effect on many audiences.
Inverted in Beauty and the Beast, The Hunchback of Notre Dame, Tarzan, and Wreck-It Ralph, however.
Limited Special Collector's Ultimate Edition: The "Black Diamond" Classics, the Masterpiece Collection, the Gold Collection, the Platinum Editions and the Diamond Editions, all of these sets being released in a wide variety of home video formats, with VHS, DVD, Blu-ray and LaserDisc being the most popular. And of course, the Disney Vault that these all get shoved into if you don't buy them now!
Special mention goes to the Masterpiece Collection, which included every VHS release at the time that was part of the Canon, including the stuff nobody remembers (like the compilation films) and the brand-new movies. From Tarzan on, they just put "Walt Disney Pictures Presents" on new releases.
Only a handful Disney movies subvert or avert this trope. In some examples, John Smith (explorer), Taran (pigkeeper/peasant) and all main characters of The Hunchback of Notre Dame (soldier, son of a gypsy, gypsy performer) are self made heroes.
Non-Human Sidekick: Most of the human main characters and/or their love interests have one, as do some human villains.
Production Posse: Check any of the credits in the Disney Animated Canon starting with The Aristocats and you'll begin to notice several recurring names in both the cast and crew. Here's a small rundown:
The Dark Age Of Disney:
Phil O'Harris, Pat Buttram, Sterling Holloway (a remnant from the studio's Golden Age) and George Lindsey.
If the film had a male child protagonist during that period, he was probably voiced by one of animator/director Wolfgang Reitherman's sons.
Time Skip: Several movies in the canon started adopting this measure beginning in the Disney Renaissance period (though it had been used since the earliest movies), and continuing to this day. It got really egregious during the height of the Disney Renaissance period, when films like Hercules and Tarzan would have two or more timeskips within the expanse of a 3-minute song.
The "Saccharine Show" part even less so with its more mature films, however.
What Could Have Been: Two books have been written on the subject, The Disney ThatNever Was and Disney Lost and Found (focusing on My Peoples and Wild Life specifically alongside deleted segments from completed works.)
Also, The Nightmare Before Christmas was apparently supposed to be Disney's 32nd animated film, to have been released during the 1993 holiday season, with The Lion King, then Disney's 33rd animated film, being scheduled for the 1994 holiday season. Then Nightmare was rebranded as a Touchstone film due to being Darker and Edgier even by Disney's standards (and some of the animated canon's entries are more mature than others) and Lion King found itself pushed forward to summer 1994 and directly replacing Nightmare as Disney's 32nd as a direct result of said rebranding. Had things gone as planned, Nightmare would've been Disney's first non-hand-drawn film in the animated canon.