* Joker (Batman 1989): Because the film makes Joker's pre-supervillain life more important and ties it with Batman's origin, he's given the name Jack Napier when in the comics his name is completely unknown. The popularity of the film means other adaptations and the comics have used the name as an alias and sometimes also as his real name.
* The Spider (Jack Staff): In the original comics the Spider's backstory and name were a mystery, but in the comic Jack Staff he was named Alfred Chinard. Notably Paul Grist had  thought the Spider was in the public domain when he had done that, but when IPC found out they allowed him to continue to use the character as long as he was only called by his real name instead of his codename. The comic Albion would also use the name Alfred Chinard, but Zip Nolan would point out it's just an anagram for arachnid and it's assumed to just be an alias.
* Rogue (Fox X-Men): I might be wrong about this, but I believe that  Rogue's real name Anna Marie  wasn't revealed until after the films came out which briefly mentioned her name to be Marie.
* Ariel (The Little Mermaid): Ariel and pretty much every character in this film from the original story, since none of them had names.
* Bane (Gotham): In the comics Bane's real name has never been revealed, assuming he even has one considering how he was raised, but the show Gotham gives him the name Eduardo Durance (a reference to Edmund Dorrance/King Snake, his dad in the comics).
* Jiminy Cricket (Pinocchio): The Disney film calls him Jiminy Cricket and is so well known most people don't know he was just called the Talking Cricket in the book.

Characters are given a name in the adaptation.