We play with the optional rule of net hits increasing drain for direct combat spells (note, it's
JUST direct combat spells) and it works pretty fairly in our campaign...
As for increasing drain dice, it's:
- Attributes
- Metamagic (Centering) with additional initiate grades
- Fetish casting
- Centering Focus
- Edge (very useful for the big spells)
I think these are the only things that will do it, but combining them gets you some pretty big numbers....
There are a few indirect ways to help as well:
-
Metamagic (Absorption) - Doesn't give you drain dice
per se, but it does just give you extra drain successes if you can get charged up... overcasting a F15 Lightning bolt with this is fun

-
Trauma Dampener/Platelets- Again, doesn't give dice, but lets you ignore a box of Stun damage (effectively reduces any stun drain by 1 box). Nice.