Ghost, Dark and Bug.
A recommended moveset for Azelf is:
Thunderbolt
Flamethrower
Psychic
Shadow Ball
That deals with all of it's weakneses.
Ghost & Flying. I believe that's it! Not dark or bug because although they're super-effective against Psychic, they are not-effective against Fighting. And not Psychic, because though it's super-effective against Fighting, it's not-effective against Psychic.
electric and ice are effective against flying
Azelf is a legendary Pokemon.
Water and Grass attacks are super effective against Onix.
Dragon types are gods, nothing is effective against dragon
Ghost & Flying. I believe that's it! Not dark or bug because although they're super-effective against Psychic, they are not-effective against Fighting. And not Psychic, because though it's super-effective against Fighting, it's not-effective against Psychic.
electric and ice are effective against flying
Metronidazole is not effective against the step throat.
fire: effective against: steel, grass, bug, ice Weak against: Dragon, water, fire, rock Water: Effective against: rock, ground, fire Weak against: water, grass, ice, dragon Grass: Effective against: water, ground, rock Weak against: grass, fire Dark: Effective against: ghost, psychic Weak against: dark, fighting, rock, steel Fighting: Effective against: dark, steel, normal, ice, rock Weak against: bug, poison, flying, psychic Not-Affected: ghost Electric: Effective against: flying, water Weak against: dragon, grass, electric Not-Affected: rock, ground Ground: Effective against: poison, steel, electric, fire, rock Weak against: bug, grass Not-Affected: flying Flying: Effective against: grass, fighting, bug Weak against: electric, steel, rock Poison: Effective against: grass Weak against: ghost, rock, ground, poison Not-Affected: Steel Dragon: Effective against: dragon Weak against: steel Steel: Effective against: rock, ice Weak against: electric, water, fire, steel Ice: Effective against: grass, rock, flying, dragon, ground Weak against: water, steel, ice, fire Rock: Effective against: flying, fire, bug, ice Weak against: rock, ground, fighting, steel Ghost: Effective against: ghost psychic Weak against: dark, steel Not-Affected: normal Bug: Effective against: dark, psychic, grass Weak against: fighting, steel, fire, flying, ghost, poison Psychic: Effective against: fighting, poison Weak against: psychic, steel Not-Affected: dark
Flying and Psychic are super effective against fighting
fire is regularly effective against ghost types
Dragon Pokemon are effective against other Dragon Pokemon.
Azelf is a legendary Pokemon.
Lightning is super effective against water. I hope this helps.
Water and Grass attacks are super effective against Onix.
Counterspell is effective against spells, not creatures.
Bug Type and Fighting Type moves are super effective against it.