**wArninG** : This will contain some spoilers Anyways... some of these are pretty obvious, but some will literally kill you... Sooo I'll get started now
1. Mirror of erised... in front of a normal mirror
2. Wait... but did you read the inscription on the top of the mirror?
3. In Harry Potter and the Philosopher's Stone, there's a portrait of Anne Boleyn, who was accused of witchcraft by Henry VIII.
4.The Leaky Cauldron sign is visible only to magic people
5. Hermione and Amortentia
6. In the Order of the Phoenix, some students are eating Cheeri-Owls cereal
7. Scarves are more than just accessories
8. Snape's first words to Harry are actually... a secret message
9. In the Prisoner of Azkaban, Malfoy's arm that was supposedly injured by Buckbeak is the one he uses to shove Neville, which shows the injury is fake.
10. In the Deathly Hallows: Part Two movie, at the end, in the battle of hogwarts, Harry, something significant from all the previous books shows up
11. In Tom Riddle's room at the orphanage, he has seven rocks lined up on his window sill, foreshadowing his seven horcruxes.
12. Oh, and speaking of Tom Riddle's meeting with Dumbledore at the orphanage, did you notice the picture of the cave in which he hid the locket?
13. In each of the movies, as the plot grew darker, so did the Warner Brothers logo at the start
14. When Neville is sent a Remembrall, it turns red, meaning he forgot something, only he can't remember what he forgot. But since he's the only student not wearing any robes, it's safe to assume that's what he forgot.
15. You can see Mcgonagall's name on a badge next to Harry's father's.
16. Oh, and speaking of which...
17. Harry's scar burns in The Sorcerer's Stone because Quirrell has his back to him, meaning Voldemort, on the back of Quirrell's head, is facing him.
18. The Ministry of Magic's access code is 6-2-4-4-2, which spells out m-a-g-i-c on a telephone.
19. In 'Prisoner of Azkaban,' a wizard is reading Stephen Hawking's 'A Brief History of Time.'
20. Severus Snape is still fighting for the good guys even when he duels McGonagall in 'Deathly Hallows — Part II.'
21. In 'The Half-Blood Prince,' Slughorn's feet give him away when he is disguised as an armchair.
22. Slughorn drinks a vial of liquid luck right before the Battle of Hogwarts in 'Deathly Hallows — Part II.'
23. In 'Chamber of Secrets,' Ron wears robes that are noticeably older and dingier than his peers', probably because they were hand-me-downs.
24. In 'The Goblet of Fire,' a reflection of Nagini slithering can be seen in the Warner Bros. logo.
25. Another option on the clock is 'dentist,' even though dentists don't exist in the magical world.
26. In 'Prisoner of Azkaban,' Newt Scamander appears on the Marauder's Map.
27. In 'Goblet of Fire,' Dobby briefly appears at the Quidditch World Cup camp.
28. In 'Order of the Phoenix,' Sirius says 'nice one, James' when Harry disarms Lucius Malfoy, the same thing he said to Harry's dad in an earlier flashback.
Are there any interesting details I haven't included? Please tell me in the comments!
Credits to https://www.insider.com/harry-potter-movies-details-you-might-have-missed-2020-6 for some of the details.