Forgetful Jones

A character whose defining characteristic is that he is ridiculously forgetful. Usually played for comedy, this trope does not cover characters with Alzheimer's or brain injuries that legitimately impair their short-term or long-term memory. Compare Absent Minded Professor

Anime and Manga

 * Yuma forgot his invitation to the WDC Finals party and forgot the Heart Pieces he spent a whole arc collecting when he went to the Finals.

Comic Books

 * Ira West (Iris' father, Wally's grandfather) in The Flash. In his first appearance, he was told Barry Allen's Secret Identity and helped create his super-compressed costume, but had forgotten all about it the next day.
 * Quinton Zempfester from Thieves & Kings.

Film
"I suffer from short-term memory loss. It runs in my family. Well, at least I think it does... Where are they?"
 * The Absent-Minded Professor (or, indeed, any Absent-Minded Professor). The original movie begins with the Fred MacMurray character forgetting his own wedding!
 * Uncle Billy in It's a Wonderful Life: Besides his big blunder toward the end of the film, an earlier scene shows him with reminder strings tied on several different fingers, indicating that he is generally prone to forgetfulness.
 * Dory from Finding Nemo

Literature

 * "Biffy" Biffen from the Jeeves stories, who has found the girl of his dreams, but can't remember her last name! Also applies to the TV show.
 * Another PG Wodehouse example: Lord Emsworth of Blandings Castle.
 * Professor Plum from the Clue book series.

Live Action TV

 * The Trope Namer is Forgetful Jones, the cowboy Muppet from Sesame Street.
 * The Saturday Night Live sketch "Mr. Short-term Memory", with Tom Hanks.

Radio

 * From The Bob and Tom Show, the Joe Johnson Memory System. The Jim Johannsen Memory System helps you remember names, phone numbers and even names with the help of Jonah Jameson.

Web Comics

 * Jade Harley of Homestuck starts out somewhat like this, hence why her fingers are covered in reminder strings.