you can be really aggressive when playing as Gandhi
I'm
usually super-aggressive when playing as Gandhi.
The Indians have the ultimate WW-busting UB, while Fast Workers means less workers means an earlier rush.
And Spi/Phi is my favourite warmongering trait combo:
Soldiers-Scientists-Soldiers-Scientists-Soldiers-etc until everyone else is dead.
I often play aggressive with HC and MM as well.
Both are Financial, which helps to pay unit and city maintenance costs, and super-early resource-free UUs make for the fastest rushes known to civ.
The bonuses from both UBs (culture and gold respectively) are useful when expanding fast, and are attached to buildings you'd want anyway when warmongering.
Plus HC can build one or two key wonders between wars, while MM can make full use of the wartime civics without losing valuable turns to anarchy.
One leader I don't war with a great deal is Lizzy. Obviously, the Redcoats have to get an outing or two. But thanks to her huge economic advantages, I simply don't need as much land as I do with other leaders.