Here you can find some concept screens from The Sims 4. I found these in the the game files, probably left there and forgotten by the designers.
Below 3 interesting screens. It's a world that you can spin around to go to another neighborhood. It was probably scrapped very early in development.
Here are 2 screens showing an early concept neighborhood. They are somewhat similar but the second one is a bit more flat and has different props like windmills and lacks a second river.
Here are two cutouts from each neighborhood and the 3rd a river delta.
Two concept screens for a possible neighborhood. The Sims 4 designers said that these screens helped inspire to create the current neighborhoods.
Below a couple of early neighborhood screens. There were a lot of these in the files (I counted well over 70), but these I found the most interesting:
Above screens are pretty different from the current neighborhood, with its many decorative old houses all cramped together, little river and even a beach. Below the neighborhood almost as we know it today.
And lastly, I found a much cooler city backdrop of Willow Creek. The first pic is the current city by night, which is pretty much just the city by day, but then in the dark, lighted up a bit.
The second is the one that's not used.