>>1534251On top of my head:
* Grisù, the fire dragon that wants to be a fire fighter (most known in Italy and Germany, I suppose, 1972)
* The Wizard of Oz has a little girl, a scarecrow, a tin man, and a coward lion.
(need to think a little longer about proper monsters - the examples that come to mind are monsters like vampires trying to live a normal life).
A lot more have normal persons ("NPCs") forced to grow and do heroic things. It's basically a staple, "from zero to hero". Some examples:
* The Hobbit / The Lord of the Rings (the hobbits are stand-ins for normal persons, not really hero material)
* Narnia, Peter Pan, Alice in Wonderland have normal children transported to fantasy worlds.
* Midkemia / The Riftwar cycle (the main character was a kitchen boy that became a mage aprrentice that got whisked away)
* Ascendance of a Bookworm (start as a sick child that is always on the verge of dying).
Animals:
* Momotaro, the hero born from a giant peach meets a talking dog, monkey, and pheasant and they set out to fight the oni.
* Town Musicians of Bremen: donkey, dog, cat, and cockerel that want to become musicians fight a band of robbers.
A lot of recent japanese series have a "reincarnated as X" theme, where X can be anything, including monsters (slime in TenShura, spider in So I'm a Spider, So What?, I think there is also a dragon hatchling one and some goblin ones) and objects (sword, vending machine,...)
In many of these examples the goal is not to be an RPG-adventurer, though.