Because boredom. More to be added soon. Comment if you want me to put you on the list.
Something important that must be noted in order to clear up any possible confusion is that the Indigo League Elite Four can be fought in either the first generation games (or their third generation remakes) or the second generation games (or their fourth generation remakes).
If I Imagined You as a Pokemon Character[]
Parax.[]
Giovanni
The boss of Team Rocket, the first major criminal organization in the Pokemon franchise, the secretive gym leader of the Viridian Gym (the eighth and final one that must be fought before fighting the Kanto Elite Four), and the father of Silver. He sees Pokemon as a business, and aims to capture strong or rare Pokemon, sell said Pokemon, and fund cruel experimental research on them. He specializes in ground-type Pokemon.
Jeremiah Garland[]
Blaine
The gym leader of Cinnabar Island and seventh gym leader that must be fought before fighting the Indigo League Elite Four in the first generation games. He is widely renowned for his intelligence. He specializes in fire-type Pokemon. He dresses up like a hippie in the anime because he doesn't like tourists.
Lord Andrew Mallace[]
Lt. Surge
The gym leader of Vermillion City and the third gym leader that must be fought before fighting the Indigo League Elite Four in the first gen games. He specializes in electric-type Pokemon.
His nickname is "The Lightning American!" Enough said right there.
G-man.[]
Steven Stone
Somebody who you periodically encounter throughout Pokemon Ruby/Sapphire/Emerald (third generation). If you have Ruby/Sapphire, he is the Hoenn Elite Four Champion and his Pokemon are in the mid-high 50s for level; if you have Emerald, he's a wandering trainer you face in Meteor Falls and his Pokemon are about 20 levels higher than in Ruby/Sapphire. Regardless, he specializes in steel-type Pokemon.
For whatever reason, the white hair is what made me relate this guy to G-man; the white hair, or the purple zig-zags on his jacket.
Captain Ned Edgewalker[]
Chuck
The gym leader of Cianwood City and the fifth gym leader that must be fought in the second generation games before moving onto the Indigo League Elite Four. He specializes in fighting type Pokemon, but for some reason gives the Storm Badge when defeated.
I figured that Ned had to be a fighting-type specialist, but all of the other ones were too skinny or too buff for my liking. lel c:
EmpressBluefeather31[]
Roxanne
The gym leader of Rustboro City and the first gym leader that must be beaten in order to fight the Hoenn Elite Four. She was one of the best students in the history of the Pokemon Trainer's School, which caused her to be immediately promoted to Gym Leader upon graduation. Her type speciality is Rock Pokemon.
John Breasly[]
Lance
The final member of the Indigo League Elite Four in the first gen games and the Champion of the same league in the second gen games. Lance is one of the toughest trainers for the player to overcome in any Pokemon games due to using dragon-type Pokemon, which is widely considered to be the strongest class in the games.
Johnny Goldtimbers[]
Spenser
The Frontier Brain (kind of like a gym leader, but no associated Elite Four and much more challenging) and master of the Battle Frontier's Battle Palace. He appears in the third generation of games, but only in Pokemon Emerald (the Battle Frontier isn't featured in Ruby or Sapphire). During the Gold Symbol challenge, he will use the legendary Pokemon Suicune.
Taylor1357, Ishmael Venables, and Lieutenant General Richard Venables[]
Team Rocket Executives
Ishmael Venables: Proton (left)
Lieutenant General Richard Venables: Archer (middle)
Taylor1357: Petrel (right)
Archer, Proton, and Petrel are a group of people that first appear in the second generation games, although without names (they get their names in the fourth generation remakes). They are three fourths of the Team Rocket Executives, the fourth being Ariana. They take over the Goldenrod Radio Tower in hopes of communicating with their missing leader, Giovanni. After the player beats Archer, however, he gives up on the mission, effectively disbanding Team Rocket.
David McMartin Son Of Sparrow[]
Brock
The gym leader of Pewter City and the first gym leader the player faces in the first generation games (and their third generation remakes). Although he doesn't play a particularly significant role in the games, he is one of the main characters in the anime for a while. He specializes in rock-type Pokemon in the games, but holds a wide variety of Pokemon in the anime.
Jim Logan[]
Norman
The gym leader of Petalburg City and the fifth gym leader the player must face in order to advance to the Hoenn League Elite Four in the third generation. Regardless of whether the player chooses to be Brendan or May, Norman is their father. However, Norman is only May's father in the anime. He specializes in normal-type Pokemon.