Remanants is often a good choice for an origin, since Megacorps tend to build taller than other empires, and it gives access to an early ecumenopolis. Void Dwellers is good too, for early trade, though more limited in build slots, and a regular empire is probably better for a Void Dwellers build, as they get Functional Architecture.
One idea I had recently, though I haven’t done a full playthrough of it yet though, is to stack Pleasure Seekers and Gospel of the Masses. You will get +20% happiness from the former and 0.5 trade value per pop, while Gospel of the Masses gives 0.33 trade value for each Spiritualist pop on your planets or worlds with branch offices.
