Question

What is the Habitat List ?

Answer 1

It is a list that shows where Pokemon lives. In Firered/Leafgreen There are 9 section for Pokemon habitats.
____
- Grassland Pokémon
- Forest Pokémon
- Water's-edge Pokémon
- Sea Pokémon
- Cave Pokémon
- Mountain Pokémon
- Rough-terrain Pokémon
- Urban Pokémon
- Rare Pokémon

//JOFLY

Comments

I can't give BA here so,+1 to both

Answer 2

The Habitat Mode is a new function in BW2, allowing the player to see every what Pokemons are available in certain locations. Once you have caugth all Pokemons in a specific habitat, it will be marked with a red Pokeball.
Source: http://bulbapedia.bulbagarden.net/wiki/PokeDex#Generation_V

Comments

I didn't know if this is what you meant, but I thought it was worth mentioning.