One combination I see based on troops you are using already and have good traits for might be something like:
Khorvash
Valk
Crimson Bat
Something else (maybe Spirit Fox to get Green/Purple, or Psion, or a second CB)
Red/Yellow banner, or Dragon banner
The goal would be to fill up Valkyrie fast, then use her to power Khorvash and CB. All of these troops do True Damage, so they ignore armor. Khorvash, Spirit Fox and Psion all drain mana from your opponent, so I find something like this to be effective and fast for PVP. Valk picks up some souls when you cast, as well.
The two fastest traitstone farming teams I’ve seen are:
Princess Elpseth (full traits)
Bombot (0 traits)
Mechanist w/Black Manacles (all traits)
Dwarven miner (or any brown only troop)
Double brown banner.
Depending on your armor bonuses the bombot oneshots an explore, or if needed finish with black manacles. This team very often finishes in under 1 minute.
Alternatively something like
Valkyrie
Rowanne
Siren
Siren
Blue/Green banner
This is also very fast but I think the elpseth team is faster.