Charmander

Squirtle

Bulbusaur

Charmander is a fire Pokemon. You can only get a charmander by trading.

Squirtle is a water Pokemon. You can only get a squirtle by trading.

Bulbusaur is a ground Pokemon. You can only get bulbusaur by trading.

Pigeotto

Pikachu

Butterfree

Pigeotto is a bird Pokemon. He is found in many places.

Pikachu is found in Viridian forest and the power plant.

The only way to catch a Butterfree is to make your Metapod evolve into Butterfree at level 10.