underwater materia:take the elevator to the junon underwater facility.there you will fight a monster called ghost ship.morph it to get guide book.trade it with kalm traveler for an underwater materia.

contain:if mideel is already destroyed,you cant get contain by "legal" means.you must feed a white chocobo some greens and then scratch the neck of the white chocobo.it will give you a contain materia.i repeat.if mideel is already destroyed,you cant get contain materia anymore,since the white chocobo is already gone.

choco/mog:talk to the chocobo's in the fence in the ranch.make them do a dance.afterwards,they will give you a choco/mog materia.

ziedrich:steal from rude in most of the battles with him.