This is an edited Sims 4 rock. The edges need to be softened quite a bit, but I thought I'd share my prototype because it is better than Pancake Land I think. I will try to make a few different shapes and sizes when I can.
I just used the grass from the top of that big grassy rock, and dirt from a sims 2 object....recolor better if you want!
Use Move Objects to raise and lower it. The footprint is on one side so it can go through foundations. Place low fencing, or objects inside to block sims from going through it.
Here there is a platform and stairs hidden inside of the hill parts.
The pumpkin chairs are by mammut.
Have fun. Play with it...see what you can do. I will try to make a better one this weekend.
A third hill has been added. It is a borderless buyable version of the debug garden hill. (The original hill was slightly softened, and the grass from the debug hill was added to the first two hills for a light green color.)
A mix of the hills used together: