The definition of 'creature' can be pretty broad, and in The Lord of the Rings world, it could include everything save for most human races: Men, Elves, Dwarves, and Hobbits.
Middle-earth is populated by a lot of the same animals that exist in the real world, but Tolkien borrowed a lot of classic critters from folklore like dragons and werewolves, and even invented a lot of his own. The beasts and monsters fans encountered during the Third Age are pretty fantastical, but if fans journey back to the Second and First Ages they will find even stronger creatures capable of ransacking cities and terrorizing entire armies. A century's worth of history took place by the time the movies arrived, and the prequel series only covers part of that history. While the world might be more familiar with the movie trilogies and the Rings of Power Amazon Prime series, they are just the tip of the iceberg.
J.R.R Tolkien was responsible for crafting one of the most epic and intricate universes full of fantastical Lord Of The Rings creatures.