From all the playable abilities in the game including the Limit Breaks is there any attack that can do more damage than Final Heaven which has potency of 9000? I see that second to that is the Black Mage's Meteor with potency of 5400 and third Bladedance with 5000.
All melee LBs do the same potency. So, technically, your answer is no, because dragoon, ninja and samurai LBs will do the same amount of damage as a monk's LB. LB damage itself is based on your party (gear) and not any one character.
From what I understand, LB3 potency wise, it's melee, caster, ranged (assuming there's 1 target).
All melee limit breaks do the same damage. All the caster limit breaks do the same as each other too. Same with the ranged physical. The tank LBs are all the same, and the healer LBs are as well.
The only factor in how potent a LB can be is the average item level of the party's weapons. There's some bosses who have certain phases where they take bonus damage but that's pretty rare. Player buffs and debuffs have no impact on Limit Break damage.
Single target melee lb hits the hardest out of anything. Depending on what you meant by most damage, caster lb does more damage on more than 1 target total, thats not factoring overkill which is rarely going to be an issue.
Mentioned in outdated wikis limit breaks potency is incorrect because they are not calculated this way. You can have i345 weapon but other party members with ilevel 1 weapon and your LB3 will be very, very weak, less than your autoattack. It's not yours 9000 potency.
No but it's definitely the coolest.