Master of Magic. It’s basically the Civilization gameplay loop, but adds fantasy creatures, magic spells, hero units and loot. There’s a recent remake but it just doesn’t capture the same vibes as the original, at least for me.
Been looking for a spiritual successor for 25 years but nothing scratches that itch.
With that said the game is widely unbalanced and full of totally broken strategies, which somehow doesn’t make it less fun.