Brock is the gym leader of the Pewter City Gym in Kanto with the ultimate goal of becoming a Pokémon Breeder and Doctor. He has been a longtime friend and traveling companion of Ash Ketchum. In fact, he’s traveled with Ash across more regions than any of Ash’s other friends.
It’s only natural that Brock would catch some new Pokémon from these regions during his travels. Despite his status as a rock-type gym leader, not all of Brock's Pokémon were rock-types. While Brock certainly hasn’t had as many captures as Ash, he's still caught his fair share of Pokémon, onscreen or off. Here are his best captures.
Geodude gets the lowest spot only because we never actually saw Brock catch Geodude. Brock already owned Geodude when Ash first battled him. However, Geodude has been a staple of Brock’s lineup since the beginning and deserves some mention.
In its first appearance, Geodude battled and defeated Ash’s Pidgeotto before being defeated by Pikachu. Geodude remained in Brock’s party until Hoenn, when Brock lent it to his younger brother, Forrest, who was watching the gym while Brock traveled with Ash. Geodude rejoined Brock in Sun & Moon where Brock compared it to the Alola Geodude. So, while its capture by Brock is never shown, it’s hard to deny such a classic of Brock's party a placement on the list.
Vulpix was given to Brock by Suzie because she saw how well Brock cared for his Pokémon, and Suzie thought that Brock could take better care of Vulpix than she could. Vulpix had trusted Brock from the get-go, which it had never done with any trainer beside Suzie. It especially loved his homemade Pokémon food.
The reason why Vulpix ranks so low on this list is that Brock eventually gave Vulpix back to Suzie. He met her in Johto, and they entered a beauty contest together with Vulpix. Despite the time that Brock and Vulpix traveled together, Brock admitted that he never really felt that Vulpix was ‘"is," and that he was only looking after it for Suzie.
As a Pokémon Breeder, Brock wanted to care for all types of Pokémon, and he had a habit of raising Pokémon with different temperaments and personalities. Brock met Mudkip in Hoenn and wasn’t dissuaded by its initial distrust toward him. Mudkip joined Brock’s team after Brock befriended it and helped it rescue a baby Mudkip.
Brock usually used his Mudkip alongside Lombre, and Mudkip often assisted Pikachu in resolving arguments with other Pokémon. Mudkip evolved into Marshtomp during a practice battle with Ash’s Grovyle. While it remained a part of Brock’s party during the Battle Frontier arc, Brock eventually left Marshtomp at the Pewter Gym when he went to join Ash in Sinnoh.
Much like Misty once received an egg as a prize, Brock received an egg in Sinnoh after he won a competition with his Croagunk. Eventually, the egg hatched into a Happiny. Brock’s Happiny had monstrous strength and was capable of lifting large boulders.
Thanks to the Oval Stone that Brock had given it when it first hatched, Happiny eventually evolved into Chansey in order to save some baby Pokémon who had been poisoned by Tentacruel. Chansey hasn’t been seen since the Sinnoh series, but it’s probably still with Brock at the Pewter City Gym. Given the care that Brock shows for his Pokémon, maybe Chansey will one day evolve into Blissey.
Brock met Lotad in Hoenn, near a Flower Shop on the road to Rustboro City. After some encouragement from Brock, it joined his team. Lotad was rather dense and slow to react, and it often had a vacant stare, but Brock was patient.
Eventually, Lotad evolved into Lombre after it fell into a well. It evolved again into a Ludicolo after accidentally touching a Water Stone. It became a much happier and helpful Pokémon after this. It enjoyed dancing, often pulling Brock along for the ride.
When Brock returned home to Pewter City, his younger siblings enjoyed playing and dancing with Ludicolo. Because of this, Brock decided to leave his Ludicolo with his family.
Brock caught Pineco near Azalea Town in the Johto region because he believed that the explosive Pokémon would be a true challenge for a Pokémon Breeder like himself—and a challenge it proved to be. Pineco tended to explode whenever it was startled, angry, or happy, and it often did so when Brock was near, for added comedic effect.
Pineco eventually evolved into Forretress in order to save Brock. Forretress was also used to help Brock capture Bonsly. Forretress helped Brock win many fights, and the two formed a strong bond. Eventually, Brock left Forretress at the Pewter City Gym when he traveled to Sinnoh to join Ash.
Brock caught Bonsly during the Hoenn series, and it was the only Pokémon that he brought with him when he rejoined Ash in the Sinnoh region. Bonsly acted like an infant, often crying when upset, and it required Brock to feed it from a bottle. Occasionally, it took the role of keeping Brock away from girls.
Bonsly eventually evolved into Sudowoodo after it freed itself and a Nuzleaf from a cage, and this was thanks to Brock’s reassurance and trust in his Pokémon. Sudowoodo bonded with Brock’s other baby Pokémon, Happiny, and the two were often seen together. Sudowoodo went with Brock to Alola and battled Olivia’s Lycanroc, proving that its bond with Brock was as strong as ever.
Croagunk is the first Pokémon that Brock caught in Sinnoh and was the main Pokémon that he relied on during that series. Initially, Croagunk was working with Team Rocket, but it switched sides and willingly joined Brock after feeling a connection with the rock-type gym leader.
Croagunk took the role of keeping Brock’s flirtatious advances with women in check; any time Brock flirted with or obsessed over a woman, Croagunk would emerge from its Pokeball and jab him with a Poison Jab. While Croagunk hasn’t been seen since Brock left Ash’s company, it’s assumed that Croagunk is still in Brock’s care and living at the Pewter City Gym.
While not shown in the anime, Zubat was Brock’s first catch after starting his journey with Ash. Zubat later evolved into Golbat while Brock was traveling with Ash in Johto, and then Golbat evolved into Crobat. Keep in mind that Golbat can only evolve into Crobat if it has a high friendship with its trainer, meaning that Golbat must've trusted Brock in order to evolve.
Brock left Crobat with his younger brother, Forrest, who ran the Pewter City Gym while Brock traveled with Ash. Crobat returned to Brock’s care by the time of the Alola series. When Team Rocket attacked Professor Oak’s lab, Brock sends Crobat to fight. Zubat was Brock’s official ‘first’ capture, and it was great to watch it grow and evolve on Brock’s journey. However, there’s one Pokémon on Brock’s team that ranks higher than Crobat.
Onix is a staple of Brock’s lineup in both the games and in the anime. Just like Geodude, Brock already owned Onix when Ash first met and battled him, but, unlike Geodude, Onix’s origins were explained and shown.
Onix was Brock’s first Pokémon and a gift from Brock’s dad, Flint, for Brock’s 10th birthday. Onix remained with Brock until he lent it to his younger brother, Forrest, when he took Brock’s role as gym leader while Brock traveled with Ash. During this time, Onix evolved into Steelix.
When Brock reappears in the Sun & Moon series, he once more has Steelix in his party. He has also acquired a Key Stone, and he can now Mega Evolve Steelix into Mega Steelix. While the rest of Brock’s party may change, Onix/Steelix has been, and always will be, a core part of his rock-based team.