Grass Type

Grass Type Pokemon know how to use their environment. Many Grass Types use Sunny Day to let Solarbeam stay charged for 5 turns. Grass Types also know how to heal themselves while attacking their opponent. Giga Drain reduces an opponent's HP and increases your Pokemon's HP. Many Grass Types are also dual types; the most common combination is Grass with Poison, meaning your Grass type Pokemon won't be vulnerable to poison. Grass Types are afraid of Poison, Ice, and Fire so if you want to use Solarbeam on one of those Water Types, watch out for their Ice Beam!

Tangela is a Grass and Poison Pokemon and doesn't evolve(3rd Generation). Tangela can be found past the fence of Pallet Town in Pokemon FireRed/LeafGreen and can learn moves like Solarbeam and Giga Drain.

Roselia is also a Grass and Poison Pokemon. Roselia can wreak havoc on your opponents Pokemon because it can learn moves like Stun Spore and Grasswhistle that will give your opponent a status condition. Roselia can also learn strong moves like Solarbeam and Magical Leaf. Magical Leaf gives an advantage to Roselia because it never misses. Sometimes, an opponent will use a move like Double Team, which will make regular moves miss, but Magical Leaf will always hit!