Heavy hitter and meth head are must pick at the beginning. Heavy hitter makes you able to stumble every mutation with one hit to weakspot even with white bat.
I prefer FYF and Numb before BL, since I usually have a good healer in party and this also reduces the trauma damage you sustain.
Sunder is solid pick early on as well if you have a mutant killer.
Vanguard lessens trauma dmg for the whole team, specially in tight spots during hordes.
HF and KI can be switched out for more support or melee cards, but it can be nice to have in certain situations where the mutation killer is overwhelmed, and with fireaxe they will melt through bosses.