The demo of the original unreleased Fading Suns, Noble Armarda rpg game. It haunts me, I see it in my dreams.
Another one is millenia: Altered destinies. You play a time traveller fleeing the destruction of your galaxy and your job is to make sure the 4 wildly different intelligent species in this galaxy evolve, survive to become interstellar, and become an equal federation (otherwise you're just swapping one death swarm for another). It's from the early 90s and has a UI I would call... formidable.
I remember that. A staple of the old freeware discs.