Charlie's the second eldest Weasley, and duirng Harry's first year Charlie agreed to take the infant dragon Norbert from Hagrid, and during Harry's fourth year Charlie came to the Triwizard Tournament for the Second Task where he helped control the dragons.
In the first book, Neville, Hermione, Harry, and Draco had detention in the Forbidden Forest with Hagrid. After Harry and Hermione were caught sneaking around after hours, Neville was caught trying to let them know that Malfoy knew, and Malfoy was caught after he tried to get them in trouble. Ron was sick in the Hospital Wing and therefore took no part in all of the drama.
Padma Patil is a Ravenclaw, although in the films she is shown as being a Gryffindor along with her sister Parvati.
Rita Skeeter was an unregistered Animagus, similar to the Marauders. Hermione caught Rita Skeeter at the end of the Goblet of Fire, trapped her in a jar that was spelled to prevent Rita from changing back, and Hermione made her promise to not write anymore false rumors about Harry.
A map of the London Underground
In Chapter 1 of the Philosopher's Stone/Sorcerer's Stone, in reply to McGonagall asking if he could do something about the scar on Harry's forehead, Dumbledore says "Scars can come in handy. I have one myself above my left knee that is a perfect map of the London Underground."
Harry Potter was only the Chosen One because of Snape. Snape overheard Trelawney making the prophecy to Dumbledore that the Chosen One was a boy born at the end of July, and Snape assumed that meant Harry because of Snape's connection to Lily. In truth, Neville Longbottom was also born at the end of July, and could just as easily been the Chosen One if Snape had not misinterpreted the prophecy.
Ginny dated Michael Corner in Order of the Phoenix, dated Dean Thomas in Half-Blood Prince, and after she broke up with Dean, she dated Harry until he broke up with her to go hunt Horcruxes.
First introduced in The Prisoner of Azkaban as being the conductor of the Knight Bus, Stan's seen again in Goblet of Fire while flirting with some girls at the Quidditch World Cup, and finally in The Deathly Hallows when Harry unmasks him during the chase. However, Stan was only a Death Eater due to being under the Imperius Curse.
Winky was the house elf of Barty Crouch, Kreacher was the house elf in Number 12 Grimmauld Place, and Hokey was the House elf belonging to Hepzibah Smith and was charged with killing Hepzibah, who was really murdered by a young Voldemort.
...A fresh pickled toad"
"His eyes are as green as a fresh pickled toad, His hair is as dark as a blackboard. I wish he was mine, he's truly divine, the hero who conquered the Dark Lord." - The love poem Ginny Weasley wrote to Harry Potter in Chamber of Secrets, delivered to Harry via a dwarf that sat on him in the corridor.
In The Deathly Hallows when the trio infiltrates the Ministry, Harry tells Mary Cattermole as they're escaping "It's the only spell she ever has trouble with" (Chapter 13).
Behind a portrait of a fruit bowl
Near the Hufflepuff Common Room, there's a portrait of a fruit bowl, and to get inside the kitchen, one must tickle the pear until it turns into a green doorknob.
Technically, Peeves is a Poltergeist. He's one of the only characters that is in every single book, and yet he's not in any of the movies.
Neville was never a Quidditch Commentator. Ludo Bagman commentated at the Quidditch World Cup. After Lee Jordan's graduation, a new commentator was needed, and both Zacharias Smith and Luna Lovegood tried out for the position at separate matches (Chapter 14 & 19).
What the Bat-Bogey Hex does for sure is never stated in the books, but it's made clear that no one wants to be on the receiving end of it from Ginny Weasley. In Order of the Phoenix, she used it on Malfoy to escape from the Inquisitorial Squad; in Chapter 6, George warns Harry against Ginny's ability with the hex. In Half-Blood Prince, Slughorn invites Ginny to join the Slug Club after witnessing her use it upon Zacharias Smith.
Set Quirrell on fire
She set Snape on fire.
Answer These 16 Questions To See If You're An Expert On The "Harry Potter" Books
It might be time for you to go over them again. Any excuse to read Harry Potter is a good excuse.
Reading the books again is always a great choice. Immersing yourself in the series again is a great way to pick up on all these details.
Maybe you don't know everything about the books, but you know enough. Rereading the books should help out with filling yourself in on any details you missed
You're an expert. JK would be proud!