Created by Level-5 and Bandai Namco, with art and animated cutscenes by Studio Ghibli (Spirited Away, Grave of the Fireflies etc.), Ni No Kuni is a great game to help satisfy your monster collecting RPG itch.
In Ni No Kuni, you play as a boy named Oliver, who has just lost his mother and only parent, and is racked with guilt. His tears bring the fairy plush toy, Mr. Drippy, back to life and they venture into the world of Ni No Kuni to find Oliver's mother and defeat the Dark Djinn, Shadar, and the titular villain of the game, the White Witch.
In addition to having different spells and abilities themselves, each of the three rotating members of your party is allowed to use one monster -- called familiars -- at a time, in which the human and their respective monster share a health bar. Similar to other games, you can capture more monsters to expand your collection. These monsters all have evolution trees as well, although sometimes changes are more subtle, such as adding accessories or just palette swapping.
The sequel, Ni No Kuni 2: Revenant Kingdom, will be coming soon -- and although the gameplay will be a bit different, playing or replaying the first game would be a good refresher before the sequel's release.