In the Pokemon anime series, Misty is the first travel partner Ash Ketchum has when he embarks on his journey to becoming a Pokemon Master. Unlike Ash who catches all types of Pokemon, Misty has a special love for Water-types. She doesn't catch too many Pokemon throughout the Pokemon anime series, though she forms close bonds with the few that she does add to her team.
Misty often feels overshadowed by her older sisters at the Cerulean City Gym. However, throughout the series, Misty proves that she is a competent Pokemon Trainer that can hold her own in a battle. Though she claims to want to be a Water-type Pokemon Master, she seems to be satisfied just making sure her Pokemon are happy.
Staryu and Starmie
Misty makes her debut in the franchise in the Pokemon Red, Blue, and Green video games. She is the Gym Leader of Cerulean City, and she specializes in Water-type Pokemon. In the anime series, she is shown to still have a great love for Water-type Pokemon, and she fills up her team with such critters. One of her favorite Pokemon is Staryu. It has powerful Water-type moves which come in handy when Misty and her friends are facing off against Team Rocket. Misty also has the Starmie on her team, which is the evolved form of Staryu. It is large enough for Misty to occasionally ride it, and when it is defeated, its points droop.
Poliwag, Poliwhirl, and Politoed
Misty rescues a Poliwag from the villainous Team Rocket, and it takes a liking to her. She decides to catch it, and it becomes a loyal member of her team. Like most of her Pokemon, Poliwag is cute, and it is a Water-type. During a battle against Ash, Misty's Poliwag evolves into a Poliwhirl. When the Pokemon is given a King's Rock, it evolves into Politoed. Although Misty wanted a Poliwrath, she learns to love her cheery Politoed.
Togepi and Togetic
When Ash, Brock, and Misty find an Egg, they fight over who it belongs to. When the Egg cracks and Togepi emerges, it takes a liking to Misty, so she gets to keep it. She never throws the baby Pokemon into battle, but it does know the move Metronome which helps the trio out when trouble comes their way. Metronome is a unique move that allows a Pokemon to use a random move. Togepi evolves into Togetic in the Ruby and Sapphire series, and she decides to part ways with it so that it can live in Togepi Paradise with the Togepi.
Azurill
Togepi's Egg isn't the only one that comes Misty's way. She also receives an Egg from Tracey who is a character that briefly replaces Brock. An Azurill eventually hatches from the Egg. Much like Togepi, Misty usually keeps Azurill outside its Egg, and she coddles it like a baby. Azurill is special because it is one of the few Pokemon that Misty owns that isn't a Water-type Pokemon. Although Azurill can evolve into Marill and eventually Azumarill, Misty's Azurill is never seen evolving.
Goldeen, Luvdisc, and Horsea
The next three Pokemon are lumped together because they all suffer from the same "fish out of water" problem. Goldeen is one of the Pokemon that are on Misty's original team. It doesn't receive much screen time because it can't battle on land. She also has a Luvdisc that she keeps in an aquarium in the Cerulean City Gym. It lives with a Luvdisc of the opposite gender that belongs to her sister Daisy. Much like Goldeen, Luvdisc doesn't receive much screen time because it lives underwater. Horsea is another Pokemon that joins Misty's team after being rescued from Team Rocket. Acknowledging that she can't let it out of its Poke Ball enough while she is traveling, she eventually leaves it in Cerulean City Gym where her sisters take care of it.
Psyduck
One of the Pokemon strongly associated with Misty is Psyduck. It joins her team entirely by mistake, and Misty is forced to look after it. She loves it because it is a Water-type, but she doesn't have the patience to deal with how foolish it is. The Pokemon seldom listens to her, and it comes out its Poke Ball at the most inconvenient times. Despite losing her temper with it a few times, Misty discovers that her Psyduck has impressive psychic powers that are of aid in times of trouble. Psyduck can evolve into Golduck, though Misty does not evolve hers.
Gyarados
Misty is very afraid of Gyarados, and it is hard to judge her for it. Gyarados is one of the most terrifying Water-type creatures around, and she had a bad experience with one as a child. When she catches her own Gyarados, she learns to overcome her fear. In Sun and Moon, she Mega Evolves her Gyarados during a battle against Ash and his Pikachu. Though the battle is fierce, Pikachu still manages to come out on top.
Corsola
Water/Rock dual-type, Corsola is also adorable, which makes it the perfect Pokemon for Misty. She manages to catch one with a Lure Ball, and she becomes close friends with her Corsola from that day onwards. The Pokemon is usually jolly, though it can sometimes hurt humans and Pokemon when it gets too excited and tackles them. Misty likely wouldn't be fond of Corsola's Galarian regional form, which is a Ghost-type that has lost all its cuteness.
Although their relationship doesn't start on a good note, Misty and Ash Ketchum end up becoming very close friends. She is also a strong enough Pokemon Trainer to give Ash a tough time when she occasionally has a friendly battle against him. Through Misty, fans get to see more of the Water-types of the Pokemon world, which can sometimes be neglected.