1. Nani from Lilo and Stitch has a poster of Mulan in her room.
2. In Aladdin, when the Sultan is playing with his figures, you can see the Beast from in Beauty and the Beast.
3. Mrs. Potts makes an appearance in Tarzan.
4. When Hercules is having his portrait painted, he's wearing a lion skin which is Scar.
5. The voice of Duke Weaselton in Zootopia is done by Alan Tudyk, who also voices the Duke of Weselton in Frozen.
6. Riley and her entire class from Inside Out are seen at the Marine Life Institute in Finding Dory.
7. The genie in Aladdin is also the vendor at the beginning of the movie.
8. In Hercules, Phil says "I have two words for you, 'I am retired." Even though it's three words, when you translate it into Greek it becomes two words.
9. The King and the Grand Duke from Cinderella show up in The Little Mermaid.
10. Belle and the Magic Carpet are in The Hunchback of Notre Dame.
11. In Big Hero 6 in the aunt's stairwell, there's a picture of a cat dressed up as Stitch.
– Cécile de Rambouillac, Facebook
12. The bootleg DVDs in Zootopia refer to Disney movies, including ones that weren't out yet like Gigantic and Frozen 2.
13. In Toy Story 3, Sid from Toy Story makes a cameo as a garbage man.
14. In Inside Out Riley's mother's lead emotion is sadness and her father's lead emotion is anger.
15. And unlike her parents, Riley's thoughts are mixed genders.
16. When Aladdin is talking to Jasmine on the balcony, the feather in his hat reflects how well he is lying. It starts all puffed up, and when she starts to suspect him it flops further and further down.
17. Aurora from Sleeping Beauty can be seen on the street in a scene in Oliver and Company.
18. Baymax from Big Hero 6 makes an appearance as a Kakamora in Moana.
19. When Sulley is in Boo's room in Monsters Inc., he picks up her toys and there's a little clown fish (Nemo) and a Jessie doll from Toy Story 2.
Submissions have been edited for length and/or clarity.