I use Alexei, Bhudd, Eyrton, Flo, Frank, Lewis, Marina, Striker.
Ironically I have the feeling as if Frank (unexpected) and Bhudd (semi-expected) often deal the killing blow. The two are literally the death of any card with 3 or less power.... and occasionally 4 power 2. Against stronger cards they get slowly unreliable and it starts depending a lot on WHEN they are played.
With those two cards, Ambre would be quite a good Leader to add. (Counterstrike - you can chose for 3 of your cards which card they fight! can be very devastating.)
Problem of AllStars? Decks with only high-power cards. Reductions _can_ be painful. Have Bhudd and Frank and face Uppers? URGS! the same and Montana? Not really that much of a problem unless all opponent's cards are >4 power... but now I am getting into details a lot