Who is the trainer with Typhlosion? I see a lot of fan arts like this one, a trainer challenging red. He always has a Typhlosion but I have never seen the other of his pokemon in any fan art. It seems like this place is Mt.Silver. 


Who is this trainer?   
What are his pokemon?   
Where is he originated from?   Games, anime, manga?
This character's name is Gold. Like Madara mentioned, he is the main character in Gold/Silver/Crystal. He is most likely from the Pokemon adventures manga (which I read).

The one facing him is most likely Red from the manga as well. I just do not remember him having a Lapras, but I do know that at the Deoxys arc of the manga he used all 3 of the Kanto starters at some point.

In the manga, Gold's team would be Sudowoodo, Ambipom, Sunflora, Politoad, Togetic and Typhlosion (as of Volume 43). He has a Pichu called Pibu, but it's more or less there for cute appeal.

This scene is most likely drawn to depict their training at Mt. Silver, or in the game where Red is like the "final boss" of HG/SS.