I'm behind by a day so posting my next two lol:
Civilization VI
#41 - Hint: This series has a lot of history, and the games contain quite a lot of it too.
Supplementary Hint: I win because I'm more cultured than you peasant.
Guessed by: TruckOSaurus
Forza Horizon 3
#40 - Hint: It's out third trip and we're going down under!
Supplementary Hint: This series is a spin-off of another series but became more popular than the original with it's large openworld.
Supplementary Hint 2: There are many upgrades in this game that can help you race to success.
Guessed by: Supermario28
I played a little bit of Civilization II when I was very young, but didn't really play it properly, I just liked to upgrade my throne room mainly. Civilization V was the first one I sunk some hours into and unlike a lot of people I see moan online I think VI is an improvement to V. It has it's problems, I don't really like the governors they introduced in the Rise and Fall expansion nor the loyalty in Rise and Fall either.
Forza Horizon 3-5 are all really quite similar (never played 1/2), 5 wasn't eligible and I hadn't played enough of it when I made the list. 3 wins over 4 just because I prefer the setting really.