I'd of course prefer situational traits, but lacking those:
Techs: Agriculture, Fishing
Traits: Organized, Charismatic
AG and Fishing will let you build work boats when coastal, and early workers will almost always have something to do when not while you research other worker techs otherwise.
Of the warmonger traits, Charismatic is the most flexible, due to the early happiness and its bonus to ALL units produced. These things lend themselves to being useful anywhere.
Organized is interesting. I take it over financial because in the early game REX/early war phase, it actually tends to be stronger (especially if you REX a large area), and that's BEFORE you get courthouses. On top of this, it makes coastal games easier with its discounts to the lighthouse. It also has better synergy with warring than financial, since you can afford the otherwise costly civics pretty easily.
Edit: Expansive is probably equal to these for overall flexibility IMO, so I'm giving it honorable mention.