In ‘The Avengers’ (2012), there is a small screen showing the heat signature in the room where Loki is being held which shows that he has a cold body temperature. That’s because he is a frost giant.
In John Wick (2014), before the action starts, John wears his wristwatch normally. But when he goes into the "battle mode", he wears them face inside the wrist, which is the way soldiers usually do it so that they could see the time while holding a rifle and to avoid reflections off the glass.
In “Split”, James McAvoy was frustrated with filming a scene with the multiple personalities talking amongst each other, and he punched a door that broke his knuckle. McAvoy filmed for three days without telling anyone about his injury and his swollen hand can be seen in one scene.
4Deathly Hallows - Part 2
In the Harry Potter and the Deathly Hallows – Part 2, during the battle of Hogwarts, one of the giants uses a broken Quidditch goal hoop as a weapon.
In the Watchmen, the Comedian's funeral has the flag draped over his coffin for service in Vietnam. There are 51 stars on the flag, because, in Watchmen's 1985, Vietnam is a state, thanks to Dr. Manhattan and The Comedian's involvement.
6Toy Story 2
In Toy Story 2 (1999), when Al is about to hang up with the Japanese Toy museum for buying Woody, he says “Don’t touch my mustache.” This is him mispronouncing. “どういたしまして” (Dōitashimashite) which means “You’re Welcome” in Japanese.
7The Pursuit of Happyness
In The Pursuit of Happyness (2006), at the end of the movie, Will Smith, who plays Chris Gardner, walks past the actual Chris Gardner whose life the movie is based on.
8Lord of the Rings
In the Lord of the Rings, you can see that Gandalf carries his pipe in his staff.
In "Her", Theodore uses a safety pin to hold Samantha up in his pocket so she can see while out on a date.
In Rampage (2018), when Dwayne The Rock Johnson's character signs "it's me" to the gorilla, he uses the American Sign Language symbol for “rock.”