Good idea. I know coming up with new types of healers is hard.
This only ones I can think of (pulling from bravely second) an undo damage type, and % based healer,
or (my idea) an over healer. Like you use a heal, and you get over healed so your hp would look like 1500/1000.

But mudra healer tho, it would be a nightmare to learn but I bet the pay off would be AMAZING