One suggestion from last year — I think it came from Adam or Nate in SF (are you guys on here yet?) — was to consider cards that you could sacrifice yourself for some expanded benefit.
Here's one we tested recently:
During play, this made a Crowne player's head explode — in a magnificently dramatic way —when our Outworld tester played three of these at once, out of nowhere, to completely diffuse a 16-point attack.
Observations? Thoughts? Reactions?