Dragon Tamers are a Trainer Class in the Hoenn, Sinnoh, and Paldea games and their remakes. They specialize in Dragon-type Pokemon or dragon-like Pokemon. I feel that they should be a Trainer Class because we don't currently have a Trainer Class that particularly favors Dragon-types like the Dragon Tamer does. They could be used in the Dragon Gym. I suggest that this Trainer Class be high-level, like Level 40-60, as Dragon-types tend to be obtained late-game in the main games and are fairly strong.
- Dragon Tamer Pokemon Pool | Show
As for biomes, I think that the Mountainous, Magical, and Evil categories would fit this Trainer Class the best. Mountainous because Dragon-type Pokemon tend to be found in mountainous biomes, Magical because dragons tend to be associated with fantasy and magic, and Evil because dragons tend to be the villains of those tales. Mesa is another option, perhaps even Redwoods. Dragon Tamers may be rarer than other Trainer Classes.
As for skins, I feel the Hoenn skin and the Sinnoh skin would work. You can find those on Bulbapedia. You could also use Lance, Iris, Clair, and/or Raihan as alternate skins.