Materia that Cloud has used in PLC at least once (or more):
-Lightning- One of the starter materia you get in the game. For some reason, I've always associated the Bolt spells with Cloud and thus always equip him with this materia. Cloud has mastered this materia.
-Ice- Leveled to ice2. Cloud doesn't like to use this one, so that'll probably end up being as high as he gets it.
-Restore- Cure, Cure2, Regen, Cure3. Everyone should have a Restore materia. Cure = your friend. Cloud's isn't quite leveled up to Regen though, so he only has Cure and Cure2.
-Seal- Silence, Sleep. Useful for avoiding killing people he doesn't want to while still eliminating them from battle. He gets practice with it using the "sleep" spell on himself when he has trouble with it.
-Time- Haste, Slow, Stop. Cloud's actually mastered this one, though for a silly reason... his cat actually likes it when Cloud uses haste or slow on him, so it's a fun way to practice materia while playing with his cat. Useful in battle as well, especially for narrow situations.
-Barrier- Barrier, MBarrier, Reflect, Wall. Cloud uses this a lot during battle due to it making him more resilient to attacks. He only recently achieved the level necessary to use Reflect, so his Reflect spells are a bit unsteady-- they can last anywhere from a minute to thirty, quite randomly.
-ChocoMog- Deathblow!!, Fat Chocobo. The epic combination of a chocobo and a moogle performing a bodyslam on the enemy. Cloud gets along well with them, though part of that is because Choco is convinced that Cloud is a baby chocobo and likes to preen him. Cloud doesn't mind, because he really does like chocobos, and Mog is pretty badass in terms of attitude (and fluffiness). Cloud's only actually summoned Fat Chocobo once, and he was more confused than anything because of it.
-All(x2)- Support materia. Attaches to other materia for mass-use on either party members or enemies, depending on the nature of the attached materia.
-Pheonix- Pheonix Flame. Summons the legendary bird of fire to inflict massive damage to the enemies with a wave of flames from the beat of its wings, whilst restoring and completely healing all party members. Activates when its master is at risk of death or has died. Used to cure geostigma and ressurect Cloud after the final battle of the Shinra-Britannian War.
Materia Cloud WILL be getting:
-Chocobo Lure- Lures chocobos to increased encounters. Cloud doesn't have this yet, but he'll pick one up from a chocobo while petting one and probably land himself getting mauled by a number of chocobo. It'll be fun.
Any other suggestions? Otherwise, I think this is going to be it. I think these materia seem to fit best.