Others

Crystal Dragon:

Well there MUST be other characters besides Ash, Misty, Brock, Tracy, TR, and Gary! These outside characters are Prof. Oak, Ash's Mother, Nurse Joy, and Officer Jenny.
Professor Oak is a famous pokemon researcher who gave Ash his pokemon trainer license and first pokemon. He temporarily takes care of the trainers' pokemon (but doesn't train them) while they aren't needed. His Japanese name is Professor Okido.
Mrs. Ketchum, Ash's mom, only appears in a few episodes, but plays an important role. She can over react with Ash's needs sometimes, probably due to the fact she never sees him most of the time. Her only known Japanese name is "Satoshi's mom"
Nurse Joy is the "Joyful" pokemon nurse. She has identical cousins and sisters all around Indigo Island, in every city. When the Pokemon League competitions start, all of them gather to assist the thousands of trainers competing. Her Japanese name is no different from English except spelling- it's Nurse Joi- of course Brock often calls her Joi-san.
Officer Jenny is a police officer who also has identical cousins and sisters around indigo island. When the Pokemon League competitions start they all gather up to watch out for Team Rocket and other crooks who might steal the pokemon. Her Japanese name is Officer Junsa.

Professor Oak's pokemon:

N/a. In the game, he has either Squirtle, Bulbasaur, or Charmander depending on the Pokemon you choose at the beginning of the game. In the TV show he takes care of your Pokemon instead of you depositing them in your PC. 

Mrs. Ketchum's Pokemon:

Mr. Mime (Mimey)

Nurse Joys's pokemon:

Chansey

Officer Jennys's pokemon:

Growlithe