Rinoa has two separate Limit Breaks: Combine, the Limit Break she starts with and which makes use of her dog Angelo and Angel Wing, which is obtained on Disc 3 and is explained below.
Angelo can learn several different Limit Breaks and a new one is obtained each time you find and read any of the Pet Pals magazines found throughout the game. The game gives you an explanation of how to learn the new moves when Rinoa first joins your team, but just incase you forgot, select the "Status" option from the main game menus and select Rinoa. From within this screen you can choose which move Angelo will learn next.
Angelo starts off already knowing Angelo Rush and Angelo Cannon. The other moves you can learn are listed below. Some of the moves are used when you select the Combine Limit Break command while some of them may occur at any point randomly during a battle.
Learned Limit Break moves:
Angelo Rush Learned from: Already Learned
Effect: When Rinoa is attacked in battle there is a small chance that Angelo will counterattack with Angelo Rush.
Angelo Cannon Learned from: Already Learned
Effect: Combine Limit Break command that does regular damage to one enemy.
Angelo Strike Learned from: [Pet Pals Vol. 1]
Effect: Combine Limit Break command that does regular damage to one enemy (stronger than Angelo Cannon)
Angelo Recover Learned from: [Pet Pals Vol. 2]
Effect: Angelo will randomly restore one party members HP.
Invincible Moon Learned from: [Pet Pals Vol. 3]
Effect: Combine Limit Break command that makes each party member invincible for a short period of time.
Angelo Reverse Learned from: [Pet Pals Vol. 4]
Effect: Angelo will randomly revive a KO'd party member.
Angelo Search Learned from: [Pet Pals Vol. 5]
Effect: Angelo will randomly steal an item.
Wishing Star Learned from: [Pet Pals Vol. 6]
Effect: Combine Limit Break command that attacks multiple enemies multiple times. A very powerful Limit Break.
Rinoa gains the ability to use Angel Wing after you have saved her from the Sorceress's Memorial. When you activate Angel Wing you will lose the ability to control Rinoa (similar to when Beserk is cast). While under the effects of Angel Wing Rinoa will cast random spells that will be much more powerful (up to 5 times more) than regular Magic attacks. Rinoa will also be immune to most status effects.
Losing control of one of your characters can be extremely detrimental. I honestly think that using Angel Wing is a bad decision.