Grass
Flying And rock
yes, aganst rock, electric, bug, fire, poison, and steel-type pokemon. Ref. <http://bulbapedia.bulbagarden.net/wiki/Ground_(type)>
Poison and Steel type moves are good against Fairy type Pokemon.
Roselia is a Grass and Poison type pokemon.
Crobat is a Poison and Flying type pokemon.
Skuntank is a Poison and Dark type pokemon.
Poison type Pokemon are weak to psychic and ground type moves.
ground and physic Pokemon are super effective against poison Pokemon
Drapion is a poison type Pokemon
Gulpin is a Poison type pokemon.
Swalot is a Poison type pokemon.
Seviper is a Poison type pokemon.