what are the effect of them?
Simple doubles the effect of each stat boost making swords dance do +4 instead of +2 but wont raise any stat above +6.
Mummy: When the user is hit by a contact move, the attacking Pokémon's Ability is turned into Mummy, overwriting the Pokémon's previous Ability. Once the new Pokemon has mummy, if they are hit the opposing Pokemon will also have mummy and the Pokemon will continue spreading to each Pokemon that makes contact with it. It has no other effect than this. The affected Pokémon's Ability returns to normal when they are returned to their Poké Ball.
Simple is an ability that doubles stat boosts or drops of a Pokemon, so a Swords Dance would get it +4 Atk stages instead of 2.
Mummy is an ability that is given to any pokenon that hits the user with a contact move, negating the enemy Pokemon's ability and continuing to spread it.