Shang Chi-Is for destroying early big cards: Death, Red Skull, Other Dinos etc.
Scarlet: Changes bad locations, you can use others like storm or rhino, but Scarlet is the cheapest and can give u pretty lucky locations to win the game though she can also cause you to lose the game, if you want to stay cheap and don't want to leave the location change to chance just go Rhino or Storm, or if you don't want a location changer at all, any 2 cost could work if.
Angela: one of the best cards in the game the deck as a lot of low-cost cards so if she starts in your hand, you can play her early and easily get her to 7 power for the energy cost of 2.
Rest of the cards speak for themselves
Keep your hand full but leave a spot or two so you can still draw into your better cards.