Mine is an Egalitarian, Xenophile, Materialist Technocracy. My guys learned long ago, that it’s best to plan ahead and live in harmony with nature and each other. They will terraform all their planets into Gaia worlds, welcome all who wish to be a part of their empire and grant equal rights and utopian abundance (Shared Burdens require Fanatic Egalitarian, too bad). I’m also thinking about vassalizing every other empire on beneficial terms, thus also making them part of my federation.
There was an empire I used to try and make in the past when the life seeded mod was updated still that was essentially just like galactic zookeepers. They would seed life on most planets in their borders and just do research and interact with them. It was always hard to make it accurately because they’re sort of xenophile as they find aliens interesting but don’t exactly treat them equally. So I always struggled with what ethics to make them other then materialist.