I haven't played Sims in years! I only every played the first one, and for a few years got obsessed with it. I do recall having kids was a bit hard work and I couldn't be bothered with them, so I'd kill them. Used to do a few other random killings, but I can't remember many now. I know I did the swimming pool with no steps, starving to death, exercising to death. Burning to death was a fun one. I'd create a load of trash and start cooking next to it to start a fire. They build walls around the fire and the sim. I think you could sell the gravestones too.
God, I sound like such an evil and sadistic person. I'm honestly really nice!