Mold Breaker would be my choice .!
-If this Pokémon attacks and the target's ability would prevent the effects of the attack from taking place, or hinder the effects of the move, the ability is temporarily nullified while the attack is in progress. Abilities that prevent status such as Limber are deactivated during the attack which allows a Pokémon that has one to be affected by the status they prevent, but the ability cures the status immediately after the attack.

Ability: NeverFull
The Pokemon with this ability takes the effect of any berry about to be used.
Outside battle effect: At the end of every battle, there is 30% chance of an Oran Berry appearing in bag, 20% chance of Sitrus Berry, 10% chance of an EV reducing berry in bag, 40% chance of nothing appearing in bag.

Pal power if u have already catched the Pokémon once and u have now two of them (trick use one and deposit one in the box) it power ups its type moves with 20

This is some my own creations :
Ability : Sore Loser
Effect in battle : When a Pokemon faints, the next Pokemon switched out into battle gets it's Attack and Special Attack is raised .
Effects outside of battle : None if you asked me .
Type of ability : Hidden
Ability: Zombiefied
Effect in battle : If the user faints in battle and then is revived and sent back in, it's primary type moves (Such as a Fire/Ghost types Fire moves or a Water/Grass types water moves etc...) gain 1.5X more power.
Effects outside of battle : If the user is fainted and revived with a Max Revive, Revive, or Sacred Ash, it gains all of it's PP for every move.
Type of ability: Regular
Ability : Slippery Body
Effect in battle : has a 40 % chance of escaping trapping moves such as wrap , whirl pool , mean look , etc ..
Effect outside of battle : Can prevent wild battles in in Icy Caves ( can be turned on and off )
Type of Ability : Regular

I don't have a name for it, but the ability I would create is one that would cause the opponent to become confused if the opponent succeeds in confusing a Pokemon holding the ability. Maybe Reverse Tempo, since Own Tempo stops confusion, and Reverse Tempo would overthrow Own Tempo.