Re:Beta, you still need to attack the Zolom yourself as him standing up, him kicking a character out of battle, and finally him using Beta, are all counterattacks he uses after crossing certain HP thresholds, and will be used in that order. Also if you're still having trouble surviving, buy some Tranquilizers and put everyone in Sadness for an extra 30% damage reduction.

In Final Fantasy XII The Zodiac Age, Lamont/Larsa has the Shades of Black technique, which uses a random Black Magic spell for no MP cost. Set him up to spam this instead of his regular attack. It will completely destroy everything in the Lhusu Mines and allow you to easily level up quite a bit if you want since the area has one of the best early grinding spots as well, but it still remains very useful when you get him again in Jahara (though by this point you can have the technique yourself).

In Persona 3, this is pretty late in the game, but you can fuse a Helel/Satan combo with Victory Cry on one of them, allowing you to use infinite Armageddons, instantly killing any encounter in the game except for the final boss (only kills one of its phases) and Elizabeth. Even at that point in the game this is still a rather crazy powerup since the enemies in Monad as well as the Reaper are seriously threatening pretty much regardless of level, but Armageddon kills them all instantly, which makes the final parts of leveling up real easy.

Trails of Cold Steel 2, maximizing evasion on Fie, enough said.