Pocket Monsters RPG was an unreleased Nintendo 64DD title. It was meant to be the first console RPG for the Pokemon / Pocket Monsters franchise.
Little info is known on the game and no screenshots have been released. It was first mentioned in a June 1997 interview with Shigeru Miyamoto. Several months later, Miyamoto and Tsunekazu Ishihara both said there were three 64DD titles in development, one of the other two being Hey You, Pikachu!, which would later be released on the Nintendo 64. At Nintendo Space World 1997, only earlier versions of Pokemon Snap and the Japanese version of Stadium were shown.
Pocket Monsters RPG fell off the radar and no other info was announced. Junichi Masuda, a major developer for Game Freak, has stated that he doesn't believe Pokemon RPGs should be on home consoles, which could be a possible reason for the cancellation. Other likely reasons are that Game Freak was developing Pokemon Gold and Silver during that period, or that the 64DD ceased production shortly after its introduction.
Two Pokemon console RPGs, Colosseum and XD: Gale of Darkness, were released for the Gamecube, but they were not developed by Game Freak, unlike the 64DD game.