It’s an old one called Antares I used to work on it’s sadly no longer active, as I did most of the system building on the last release/update I still have the mod files.
I think it was around the same size as Discovery 100+ systems, 300+ bases and about 250 ships (fighters and capital), although it had a non dynamic economy the economic structure was large and complex and paid as well(or better) than most missions.
The MOD DB page is still there but the site links are broken