For someone not advancing Sea of Sorrow atm, on my alt with a smaller collection I’ve been using Flammifer, Tesla, Tai Pan, Soothsayer (Meteor Banner).
A note to all (and I’ll be mentioning this in this Tips and Tricks thread as well: Tips and Tricks - #28 by Clark) - you can maximise your points in any Faction Event by tackling rooms with the highest multipliers first. As you get 200 x multiplier points per room (and 400 x for a boss room), the quicker you can increase your multiplier, the better. I do it the other way around for regular Delves to try to get an extra Runic Traitstone from the higher rarity rooms (although really I don’t think it matters THAT much).
EDIT: I’ve been notified that this advice will probably only be valid until 4.1, as per Changes to Faction Events).
EDIT 2: Advice is still valid!!! 
you’re all welcome 
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