Levitate: Immune to Ground-type moves, Spikes, Toxic Spikes, and Arena Trap.
Magic Guard: Only takes damage from direct attacks (Immune to damage from Toxic, Life Orb, Leech Seed, etc).
Overcoat: Doesn't take damage from weather.
Hidden
Dry Skin: In sunny weather, lose 1/8th max HP each turn. In rain, restore 1/8th max HP each turn. Takes 1.25x damage from Fire-type moves and absorbs Water-type moves to restore 1/4th max HP.