LiquidOxygen80: Rise and Rule of Ancient Civilizations. Like AdCiv, it's not easy to find, and requires a few things to get to run, due to its 16 bit era windows status, but, I feel like it got unfairly maligned as a Civ clone, while it really didn't have tons in common with that game. It may be too much of a pain to acquire for you, though, so I'd only attempt to find it if you're really curious.
OldFatGuy: Oh man oh man I wish I could play that again. I really enjoyed that game (something about the music really did it for me in that one.) And I loved having different cities focus on one branch on research and watching the philosophers spread the knowledge around.
Just for nostalgia purposes I so wish I could play that again but I would have no idea where to find it or how to get it to run if I did find it. Wish GOG would get it. Instabuy.
EDIT: LOL, I still have the CD! Thought I did.
Here is the wishlist page for Rise and Rule if anyone is interested and hasn't yet voted for it.
Votado! I actually had a lot of fun with it, and like a lot of Sierra games back then, the music was great and memorable. I had to go the abandonware route myself, and run it via a Windows 3.11 shell via DOSbox, but it runs and is a pretty good nostalgia play for me.
OldFatGuy: I found a download of Rise and Rule of Ancient Empires. And the cool thing is, all I had to do was download it (342MB), then unpack it, and when it unpacked it created a directory with a BAT file in it that all I had to do was double click. And voila.... I"M PLAYING RISE AND RULE OF ANCIENT EMPIRES!!!
LOL, I thought I'd never play that again as I had tried using the CD to install it on a couple of computers over the past 10 or 15 years but with no luck.
Oh man... that nostalgia... it's thick. And just wonderful. Almost making me emotional I remember so many hours playing this game back in the 1990's. (When I was just MIDDLEAGEDFATGUY. lol. And could walk!)
I had to do the same thing with Warlords 3, because it's a bitch on a bitch boat to get running natively AND/or you have to pay full retail to some dodgy site that has a lot of the former Red Orb strategy games on it.
Speaking of, if DaCosta hasn't checked out Warlords series at all, I 100% recommend checking it out, even if its just Warlords 2's Deluxe edition.
Also I feel like I'd be remiss if I didn't also mention Empire of Fading Suns. It's like Panzer General, only with space, space naval battles, ground war battles, researching, noble houses with traits, etc. I feel like it was criminally slept on, much like the Fallen Haven/Liberation Day series.