Generally they are earned as Tournament or Event rewards.  Usually also some shop packs with them in them but normally those aren't super high value.

12.3 brutal 

Some peeps like 12.6 better. 😂 

I guess I actually run more normal campaign then brutal these days

Really?  Why?  Just to use less energy on dailies?

Yep. Only time I run brutal is if there's champ training going on and I'm not double dipping anywhere else.

Samsies.  Normal 90% of the time.  Ive got food coming out of my ears as it is.