Get 32,000 BP at battle square, then exchange them for Cloud's level 4 limit break, Omnislash
After stopping the train from ramming into North Corel, talk to the lady in the middle tent on the west side of town. She'll give you Barret's level 4 limit break, Catastrophe.
Go to Nibelheim and play these notes on Tifa's piano: X, Square, Triangle, R1+Triangle, R1+Square, C, Square, Triangle, R1+X, Circle, X, Square, X. You'll get the Final Heaven Limit Break Manual.
Go talk to the sleeping man by Junon when the last 2 digit's of the # of battles you fought is the same. He'll give you Mythril that can be exchanged for the Great Gospel Manual at the weapon's guy's house. It's in the small box.
Beat the Lost Number boss after opening the safe in the Shinra Mansion. You'll get the Cosmo Memory limit break manual.
Go to the crashed Gelinka once you get the submarine and go to the cargo bay. In one of the chests is Cid'd level 4 limit break manual.
Go to Lucrecia's Cave with Vincent once you have the submarine or Gold Chocobo during the 3rd disc. You'll get the limit break as long as you visited there with Vincent during disc 2.