but instead of healing they regen mana
Thats a very nice idea. In fact I thought about this before but never made a post about it.
Also, perhaps a minion type that does no damage, but drains mana
This doesnt look that interseting, whats the point of have a minion that does no damage. Unless its reallly cheap. But if it does damage, it would make LE and Oak minions builds even more powerful!