There's Freeciv [1] for IV, and Unciv [2] for V. I doesn't have many fans, VI is too recent, and VII, well... Let's not talk about VII.
> Civ fans tend to prefer [...]
I'd say, each entry in the series gets love. The saying goes: "Your favorite Civ game is the first one you ever played". In my experience, that's pretty true (Still stuck on V).
Interestingly enough, the Call to Power series was unaffiliated with Sid Meier's Civilization and was developed after Activision licensed the name from the board game Civilization was unauthorizedly based upon. There was a sequel called just "Call to Power II" in case you missed it, which had it's source code released in 2003 in case you're feeling nostalgic.
I think the first Civ I played WAS III (maybe II at a friend's house once before?) and it ain't my fav. It sits below IV and V and even VI and I don't really like VI all that much either...
> Civ fans tend to prefer [...]
I'd say, each entry in the series gets love. The saying goes: "Your favorite Civ game is the first one you ever played". In my experience, that's pretty true (Still stuck on V).
[1] https://www.freeciv.org/
[2] https://github.com/yairm210/Unciv