So, as one of my little "projects," I went through the list of Disney movies and found what I think is every Disney princess ever. Plenty of ones that the franchise doesn't officially recognize, naturally. So here:
Minnie Mouse (The Three Musketeers) - I imagine Minnie and Daisy both appear as princesses at some point, but this is the only MOVIE where Minnie shows up in royal garb.
Snow White (Snow White and the Seven Dwarves) - Straightforward enough, right?
Faline (Bambi) - Bambi takes over as prince of the forest, ergot Faline is a princess. Deer princess! :D
Cinderella (Cinderella) - Again, not a ton of explanation needed here.
Mary Tudor (The Sword and the Rose) - Historical fiction romance movie. Apparently. Mary Tudor was a younger sibling of an English king.
Aurora (Sleeping Beauty) - Third official Disney princess.
Elspeth (Dragonslayer) - Really obscure movie, from what I can gather. Pretty obvious why Disney never recognized this one - *spoiler alert* she commits suicide.
Eilonwy (The Black Cauldron) - A lot of people think she should be recognized as one of the Disney princesses - she has the right sort of personality. Then again... was it ever proved that she was actually a princess? Other than introducing herself as Princess Eilonwy and having a magic... thingy... bond with her, we don't actually have any evidence - no crown, or kingdom, or anything.
Attina (The Little Mermaid) - Ariel's sister #1. All of them are princesses, right?
Aquata (The Little Mermaid) - Ariel's sister #2.
Andrina (The Little Mermaid) - Ariel's sister #3.
Arista (The Little Mermaid) - Ariel's sister #4.
Adella (The Little Mermaid) - Ariel's sister #5.
Alana (The Little Mermaid) - Ariel's sister #6.
Ariel (The Little Mermaid) - The Little Mermaid herself, of course.
Belle (Beauty and the Beast) - A.k.a. "Beauty." Disney-recognized.
Jasmine (Aladdin) - Disney-recognized, though that is a bit strange to me because she isn't even remotely the main character. I'd list her after Aladdin, the genie, the monkey, the bad guy, and possibly even some other people. As I recall, she doesn't have many lines.
Nala (The Lion King) - Simba's mate, right? Same situation as Faline. (I didn't count Simba's mum because we only ever see her as a queen. Though that line's a little fuzzy - after all, they don't have official lion "marriages," nor does the royal line necessarily work in the same way as that of, say, England.)
Pocahontas (Pocahontas) - The daughter of a chief - I think that counts, don't you? Pocahontas is sort of "half"-Disney-accepted - she shows up in some places, but not others.
Sarah (A Kid in King Arthur's Court) - Yeah, some minor character in a medieval-theme comedy.
Katey (A Kid in King Arthur's Court) - Same as above.
Megara (Hercules) - Ah yes, Meg, of course. Hercules is the son of the leader of the gods - that makes him a prince, right?
Guinevere (A Knight in Camelot) - Queen Guinevere. I'm never sure whether to count her, because I think she went from being a noble to a queen in one ceremony. Plus, of course, she's only a minor character here.
Kiara (The Lion King 2) - Simba's daughter, from the sequel. Also a princess, then.
Atta (Bug’s Life) - They even call her "Princess Atta," and she takes over as queen later.
Dot (Bug’s Life) - Atta's little sis.
Melody (Little Mermaid 2) - Another sequel offspring princess. She's got royal blood from both parents, unlike most.
Lalala (The Emperor’s New Groove) - A minor character, from what I can gather. I've never seen the movie.
Kida (Atlantis) - According to the Disney Wiki, even, she's the daughter of the King of Atlantis and later takes over as reigning monarch.
Mia (Princess Diaries) - I'm familiar with this movie through my mom, and Mia is undoubtedly a princess. That's what the whole movie is about.
Winnifred (Once Upon a Mattress) - Apparently they made this into a movie? I had no idea. But Winnie does marry the prince at the end.
Giselle (Enchanted) - Of course. I really don't get why she isn't Disney-accepted, except that she was non-animated most of the time. Plus, well, was she a princess before she got engaged to the prince? I think so. They never explained why she was living in a cottage in the woods by herself, though.
Nancy (Enchanted) - She ends up marrying the prince, of course.
Rosalinda (Princess Protection Program) - The princess who needs the protecting.
Ponyo (Ponyo) - Ponyo! Princess of the sea. I should really see this movie. I guess she wasn't accepted because she was a Miyazaki creation. If you ask me, though, she should've been counted.
Tiana (Princess and the Frog) - Ayup. Disney-accepted as well.
Rapunzel (Tangled) - Two Disney-accepted in a row, yay! I like Rapunzel.
Tamina (Prince of Persia) - She's sort of the co-main character, and definitely a princess.
Merida (Brave) - Meridaaa! Disney-accepted (thank goodness).
Vanellope von Schweetz (Wreck-It Ralph) - She turns out to be a princess at the end, according to my little sis (who has seen it). They don't count her because it would be a spoiler alert, I bet.
Sofia the First (Sofia the First: Once Upon a Princess) - She's also half-counted, since she's a Junior star, and also originally a TV show character rather than a movie one. The whole series revolves around her being a princess, though.
Anna (Frozen) - Anna!
Elsa (Frozen) - ELSA! My personal favorite (just a couple notches above Faline).
Ivy (The Sofia the First TV Show) - This one isn't from a movie - I just happened to stumble across her. She's definitely not counted because she's, well, evil.
By the way - Mulan (Mulan) … Well... I'm afraid Mulan's not really a princess, guys. Not from what I know. She's a noble, and she marries a general, right? Correct me if I'm wrong, but I don't think that makes her a princess. Neither her or her spouse is even remotely related to the Emperor.
Minnie Mouse (The Three Musketeers) - I imagine Minnie and Daisy both appear as princesses at some point, but this is the only MOVIE where Minnie shows up in royal garb.
Snow White (Snow White and the Seven Dwarves) - Straightforward enough, right?
Faline (Bambi) - Bambi takes over as prince of the forest, ergot Faline is a princess. Deer princess! :D
Cinderella (Cinderella) - Again, not a ton of explanation needed here.
Mary Tudor (The Sword and the Rose) - Historical fiction romance movie. Apparently. Mary Tudor was a younger sibling of an English king.
Aurora (Sleeping Beauty) - Third official Disney princess.
Elspeth (Dragonslayer) - Really obscure movie, from what I can gather. Pretty obvious why Disney never recognized this one - *spoiler alert* she commits suicide.
Eilonwy (The Black Cauldron) - A lot of people think she should be recognized as one of the Disney princesses - she has the right sort of personality. Then again... was it ever proved that she was actually a princess? Other than introducing herself as Princess Eilonwy and having a magic... thingy... bond with her, we don't actually have any evidence - no crown, or kingdom, or anything.
Attina (The Little Mermaid) - Ariel's sister #1. All of them are princesses, right?
Aquata (The Little Mermaid) - Ariel's sister #2.
Andrina (The Little Mermaid) - Ariel's sister #3.
Arista (The Little Mermaid) - Ariel's sister #4.
Adella (The Little Mermaid) - Ariel's sister #5.
Alana (The Little Mermaid) - Ariel's sister #6.
Ariel (The Little Mermaid) - The Little Mermaid herself, of course.
Belle (Beauty and the Beast) - A.k.a. "Beauty." Disney-recognized.
Jasmine (Aladdin) - Disney-recognized, though that is a bit strange to me because she isn't even remotely the main character. I'd list her after Aladdin, the genie, the monkey, the bad guy, and possibly even some other people. As I recall, she doesn't have many lines.
Nala (The Lion King) - Simba's mate, right? Same situation as Faline. (I didn't count Simba's mum because we only ever see her as a queen. Though that line's a little fuzzy - after all, they don't have official lion "marriages," nor does the royal line necessarily work in the same way as that of, say, England.)
Pocahontas (Pocahontas) - The daughter of a chief - I think that counts, don't you? Pocahontas is sort of "half"-Disney-accepted - she shows up in some places, but not others.
Sarah (A Kid in King Arthur's Court) - Yeah, some minor character in a medieval-theme comedy.
Katey (A Kid in King Arthur's Court) - Same as above.
Megara (Hercules) - Ah yes, Meg, of course. Hercules is the son of the leader of the gods - that makes him a prince, right?
Guinevere (A Knight in Camelot) - Queen Guinevere. I'm never sure whether to count her, because I think she went from being a noble to a queen in one ceremony. Plus, of course, she's only a minor character here.
Kiara (The Lion King 2) - Simba's daughter, from the sequel. Also a princess, then.
Atta (Bug’s Life) - They even call her "Princess Atta," and she takes over as queen later.
Dot (Bug’s Life) - Atta's little sis.
Melody (Little Mermaid 2) - Another sequel offspring princess. She's got royal blood from both parents, unlike most.
Lalala (The Emperor’s New Groove) - A minor character, from what I can gather. I've never seen the movie.
Kida (Atlantis) - According to the Disney Wiki, even, she's the daughter of the King of Atlantis and later takes over as reigning monarch.
Mia (Princess Diaries) - I'm familiar with this movie through my mom, and Mia is undoubtedly a princess. That's what the whole movie is about.
Winnifred (Once Upon a Mattress) - Apparently they made this into a movie? I had no idea. But Winnie does marry the prince at the end.
Giselle (Enchanted) - Of course. I really don't get why she isn't Disney-accepted, except that she was non-animated most of the time. Plus, well, was she a princess before she got engaged to the prince? I think so. They never explained why she was living in a cottage in the woods by herself, though.
Nancy (Enchanted) - She ends up marrying the prince, of course.
Rosalinda (Princess Protection Program) - The princess who needs the protecting.
Ponyo (Ponyo) - Ponyo! Princess of the sea. I should really see this movie. I guess she wasn't accepted because she was a Miyazaki creation. If you ask me, though, she should've been counted.
Tiana (Princess and the Frog) - Ayup. Disney-accepted as well.
Rapunzel (Tangled) - Two Disney-accepted in a row, yay! I like Rapunzel.
Tamina (Prince of Persia) - She's sort of the co-main character, and definitely a princess.
Merida (Brave) - Meridaaa! Disney-accepted (thank goodness).
Vanellope von Schweetz (Wreck-It Ralph) - She turns out to be a princess at the end, according to my little sis (who has seen it). They don't count her because it would be a spoiler alert, I bet.
Sofia the First (Sofia the First: Once Upon a Princess) - She's also half-counted, since she's a Junior star, and also originally a TV show character rather than a movie one. The whole series revolves around her being a princess, though.
Anna (Frozen) - Anna!
Elsa (Frozen) - ELSA! My personal favorite (just a couple notches above Faline).
Ivy (The Sofia the First TV Show) - This one isn't from a movie - I just happened to stumble across her. She's definitely not counted because she's, well, evil.
By the way - Mulan (Mulan) … Well... I'm afraid Mulan's not really a princess, guys. Not from what I know. She's a noble, and she marries a general, right? Correct me if I'm wrong, but I don't think that makes her a princess. Neither her or her spouse is even remotely related to the Emperor.