Carnivorous plants began to interest me when I played Sim Earth.
In the game, you oversaw the planet's evolution and the evolution of animal varieties from primitive forms into sentient, intelligent ones. Besides Mollusks, Mammals, and other kinds, there was a very unusual one - carniferns. There were perhaps a dozen or more varieties of carnivorous plants, and they were need because they were plants that were like animals. It turns out, that in the Sim Earth story they developed the ability to walk too, and were preceded by Venus Fly Traps. The player was able to evolve them too into sentient creatures and then into civilizations. Unlike the other creatures in the game, the player could not create them directly, but they would evolve and appear naturally on the screen when there were insects.
Here is a display of basic animal types in the game, although there were other varieties:
(The Carniferns are after the insects)
Here is a display of a screen of the world with different types of carniferns and insects:
*Moderator note: While this game may be considered "abandonware" technically and legally Maxis still holds the copyright for this software. I find no evidence that Maxis has designated this title as "freeware".