I’ve been playing the early release Furthest Frontier which has been good. Not buggy for me, though it is lacking a decent endgame IMO.

Age of Empires is a pretty standard one, though more war focused than exploration/growth.

I’ve played They are Billions and it’s pretty good, though general online consensus is that the campaign is entirely unforgiving if you use your upgrade points in an unoptimized way, but is otherwise good. The one offs are fun and overall a well designed game.

On a smaller scale, This War of Mine is a really good game, though not quite a full colony sim it hits the same itch for me and has a lot of stark and rough choices.