Natural abilities
Koffing have the ability Levitate. Levitate causes all Ground-type moves to miss Koffing. Lighter-than-air gases in its body keep it aloft. The gases not only smell, they are also explosive.
Does Weezing have levitate?
Pokémon Adventures
Koga's Weezing and Koffing are revealed to have Levitate as their Ability. Agatha's Gengar was revealed to have Levitate as their Ability.
Does Gardevoir levitate?
"An Embrace Pokémon. Despite its elegant and feminine features, there can be male and female Gardevoir. A Psychic-type, it has the ability to see the future and levitate. It's a brave Pokémon who will risk its own life to protect its trainer.
