"Indigo" likely refers to the Pokemon anime series "Pokemon: Indigo League" which was based on the Pokemon video game "Pokemon Red and Blue." In these games, Charmanders can be found in:
* Viridian Forest: This is the most common location to find a Charmander. It has a low encounter rate, but it's the only place you can catch a Charmander in the wild.
* Trade: You can trade for a Charmander with other players.
However, you cannot catch Charmanders in the wild in Pokemon Indigo League.
Hope this helps!