The Pokémon anime follows Ash Ketchum as he travels around the known world, training to become a Pokémon Master. The bond between Ash and his Pikachu is one of the show's central themes, showcasing the ideal relationship between a Trainer and their Pokémon.
Like Ash, several other characters in the anime have a trademark Pokémon that becomes part of their identities as Trainers. Whether they use it as their ace in battle and contests, or simply as a constant companion to keep outside of their Pokéball, these Trainers are inseparable from their trademark Pokémon.
Bonnie & Dedenne
Because of her age, Bonnie can come across as somewhat annoying. Her obsession with setting Clemont up with girls is particularly jarring. However, she's also very sweet and ive, acting like a little sister to Ash and especially Serena.
Bonnie and her Dedenne are inseparable in the anime. Clemont catches Dedenne, one of the cutest Electric Pokémon, and gifts it to Bonnie, marking the beginning of a beautiful relationship. Bonnie doesn't use Dedenne in battle because she's too young to be Trainer, but her spirited attitude might make her an undeterred challenger in the future.
Lillie & Snowy
Lillie is one of Ash's classmates in Alola. She begins the series as a sweet yet shy girl traumatized by an encounter with the Ultra Beast Nihilego, an event that left her terrified of Pokémon. She can barely approach them and freezes in their presence.
With Ash's help, Lillie eventually overcomes her fear and befriends an Alolan Vulpix, which she names Snowy. Lillie and Snowy's partnership is very wholesome and one of the few examples where a character bonds with a Pokémon over time and not instantly.
May & Torchic
The Hoenn season was the first not to feature Misty, and May had big shoes to fill. Fortunately, she quickly earned fans' sympathy thanks to her enthusiasm and relatable struggles. May suffered from security issues, something many fans identified with, but she overcame them with the help of her friends and Pokémon.
May chose Torchic, one of the best Fire Starters in Pokémon, and trained it until it was strong enough to become a Blaziken. In fact, May's Torchic is one of the few Starters who reach their final stage during their respective season. May and Blaziken were an incredible team in Contests, and their partnership was truly one-of-a-kind.
Goh & Scorbunny
Goh is one of Ash's most likable companions in Pokémon. He's the current deuteragonist of the Journeys season, a young boy who dreams of catching all Pokémon inspired by his encounter with the Mythical Mew.
Like Ash, Goh has several Pokémon under his belt, but none measures up to his Starter, Scorbunny. After constant battling and training, the fire bunny is now a Cinderace, confirming Goh's skills as a Trainer. Goh once tried releasing his Starter, then a Raboot, but the bunny refused to leave him, cementing the pair as one of the closest Trainer-Pokémon duos in the anime.
Iris & Axew
Iris is a divisive figure among the fandom. She is stubborn and prone to hissy fits yet constantly criticizes and mocks Ash for considering him too immature. Still, Iris is a tough Trainer on her way to becoming a Dragon Master. When Ash revisits her in Journeys, Iris is already the Unova Champion, an impressive feat that leaves Ash stunned.
Her Ace Pokémon and constant companion is Axew. Like Pikachu, Axew travels outside its Pokéball, often carried by Iris. In Journeys, fans learn it has already evolved into a powerful Haxorus, one of the best non-legendary Dragon-type Pokémon. It was great seeing how far Axew had come, all thanks to Iris' love and .
James & Weezing
Team Rocket are the de-facto antagonists of the show, but they're hardly dangerous. If anything, they're good guys by now, mainly thanks to their stupidity. Over the years, Jesse and James have had many Pokémon, but a few stand out for each.
James' bond with Koffing was undeniable. It was his first Pokémon, and fans saw it grow into a Weezing. James released Weezing after it became the leader of a group of wild Koffing, understanding the inexperienced Pokémon needed it more than he did. It was a beautiful and heartbreaking moment and one of the most iconic Team Rocket scenes in Pokémon.
Jessie & Arbok
Like James, Jessie has had a wide variety of Pokémon on her team but remains closely associated with her first one, Arbok. Fans first meet it as an Ekans until it evolves into the more powerful and menacing Arbok.
Jessie and Arbok go through a lot together, and despite her villainy, she deeply loves the purple cobra. Like Weezing, Arbok becomes the leader of a pack of wild Ekans, and Jessie releases it so it can stay in the woods protecting the weaker Pokémon. Jessie also develops close bonds with many of her latter Pokémon, particularly Dustox and Wobbuffet, but Arbok always has a place in her heart.
Dawn & Piplup
Dawn is Ash's companion throughout the Sinnoh region. She's a confident and highly spirited girl on her way to becoming a great Pokémon Coordinator like her mother. Dawn chooses Piplup as her Starter, always keeping it outside its Pokéball.
Piplup is already cute, but its expanded role in the anime cemented it as the best Water Starter in Pokémon. Together, Dawn and Piplup live exciting adventures and even win the prestigious Wallace Cup. Like Pikachu, Piplup never evolves, but Dawn doesn't seem to mind.
Brock & Onix
Brock has a special place in Pokémon history as Ash's first male companion. He is a Rock-type specialist and the former leader of Pewter City's Gym. Eventually, he abandons his Trainer career and opts to become a Pokémon Doctor.
Brock's initial team was small but meaningful. In the anime and the games, his ace is Onix, which eventually evolves into Steelix. Onix is powerful and menacing, giving Ash and Pikachu considerable trouble during their first fight. Brock's team later grows to include a Vulpix and a Happiny, but Onix remains his most significant Pokémon.
Misty & Togepi
Ash and Misty have a confrontational relationship for most of their time together. Still, she remains his most famous female companion, and more than one fan would love to see them get together eventually. Misty is also one of the best Gym Leaders in Pokémon, specializing in Water-types.
Ironically, Misty's constant companion isn't a Water-type. Indeed, Togepi is her true best friend; she got it as a newborn, and Togepi immediately imprinted on her, believing her its mother. Misty eventually releases Togepi, by then a Togetic, in a very emotional scene that marked the end of an era in the Pokémon anime.