Generation Iv
No Guard
Ensures the Pokémon and its foe’s attacks land.
Detailed Effect
Moves used by or against this Pokémon never miss. One-hit KO moves are unaffected. Moves affected by this ability can hit Pokémon during the preparation turn of moves like Dig or Fly. Overworld: If the lead Pokémon has this ability, the wild encounter rate is doubled.
Pokémon With No Guard
13 canonical Pokémon forms can have this Ability.

Machop 
Machoke
Machamp
Honedge
Doublade
Mega Pidgeot
Machamp Gmax
Mega Hawlucha
Mega Raichu Y 
Karrablast
Golett 
Golurk
Lycanroc Midnight