Forbidden Flame

Some of the Forbidden Flame uses I can think of (saw in comments that it is mage?):

1. Pyromancer - free 1 damage, similar to Circle of Healing
2. Classes that cannot activate/kill your own minions easily
3. Warrior - another way to activate your own minions e.g. Gromash Hellscream, Patron, Frothing Berserker, enrage minions
4. Spelling enhancing minions - can activate or kill minions. Imagine with Malygos.
5. Mage - free fireball with Antonidas. Free 2 damage with Flamewaker

However, some general consensus is that mage spells are much better than Forbidden Flame but it is more flexible.

Forbidden Shaping

1. Help smooth out your mana curve
2. Late minions can be game changing esp. at 8 or 9 mana.