What solo games do users recommend ?

Hi, I'm new to ZunTzu and it's just in the last few month that I've spent the time to find out what an amazing app it is and played through some games with some friends.

However, I'm also very interested in the potential for solo games and was curious what games users who have been here for a while recommend for solo play ? I've been looking at Blue & Gray, and that looks a very good option, but maybe there are other games even specifically designed with solo setups in mind so any recommendations would be great.
I mostly play The Star Trek Deck Building game and personal copies of Field Commander Rommel and U-Boat Leader. Carrier is quite awesome if you have the patience to learn it.