Well, there is Guiding Light which boosts your healing spells by 40%. At least I think it was 40%. Maybe more or less, not sure. It is a life spell that you learn in a spell quest for your teacher. There are also treasure cards for it that you can get.
Guiding Light is +30% to next heal, but a normal card, not a treasure card that modifies other cards. Doing that as a treasure card that modifies other cards would make it of rather limited utility to most classes.
The treasure card Guiding Light and (I believe) the amulet card Guiding Light are +40%. The learned spell Guiding Light may be only +30%.
If there were an enhance card for healing similar to Tough or Keen Eyes, then Life wizards could make treasure cards of their school heal spells that cannot be bought in the library. This would mean any class wizard could acquire a Unicorn or Fairy treasure card through friendship or trade, which is currently not possible. I like the idea!
I have wondered how it affects game balance when spells that were designed to be school-specific are widely distributed as player-crafted treasure cards. I know I keep several wizards of different schools on my account and use them to make treasure cards for each other, including heals such as Helping Hands and Pixies. This may give me an advantage in the arena over people who don't have time to do that. Quizzical, you seem to know a lot about balance in MMORGs in general -- any opinions on the pros or cons of injecting large quantities of player-crafted heals into the game?