If you only want planets, unlike Maelstrom, Infinite Space is the main mod still in development. The one with an Urban planet with over 1000 population was probably a classic mod called Sins plus, which has been kept updated for each version, including Rebellion, on ricks galaxy.

Also, the official Forbidden worlds DLC adds 4 new planets a new planet specialization mechanic that can let you get old fashioned terran planets to 1000 population. A much more balanced way to get that high of a population IMO since you have to pay for it (Sins' plus Urban planet felt extremely OP to me).

IIRC large total conversions like Armada may not work when you enable it in game, you may have to edit the enabledmods.txt file directly. Also they recommend lots of other odd changes like enabling LAA, so you should probably ask on their thread and read all of their instructions carefully.

Well, I include an optional addon for my Enhanced 4X mod that disables them. There might be one floating around for Vanilla Sins as well, but these kind of things tend to be mod specific so it wouldn't work for Maelstrom or Armada (if it has superweapons). There's no way to disable them without a mod.

Ok looks like you were right again, the thread on MOD db says you have to overwrite the enabledmods.txt file with the one that comes in the zip, i am assuming just pulling the old one out and leaving the new one while i play star trek should work, then replace if i want to play the others should work, i will try this and see.

thanks for the pointer.