I don't know... I just wanted to do something fun.
So... Yeah, design your own Blue Mage spells!
They can be OP spells to have fun with, they can be balanced spells to fit a "Unlimited" BLU, they can be from previous games, from enemies in games or heck maybe design some skills based on Duty Bosses!
Anything goes!
Examples:
Bubble Shower - Deals Water damage with potency 130 to all targets in a cone in front of you.
Source: Megalocrabs
Universal Manipulation - Deals unaspected damage with potency 200 and inflicts a plethora of status ailments to all targets within 20 yalms.
Source: Ascian Prime
Goblin Punch - Deals physical (Blunt) damage with potency 30 to target. If the target is the same level to the caster (Or level ??) it deals 240 potency instead.
Cooldown: 90s
Source: Whalaqee Totem