I hate looking for floorplans but I’m too impatient to create one all by myself. That’s where this website comes in. The Make Room allows you to create a room (even place furniture). You have two options upon entering: Make your own plan (by entering your own dimensions) or select a premade plan and edit it.
Mostly it helps me place furniture and then I can freely place walls where I want while in game. It saves me a lot of time editing and reediting rooms when furniture doesn’t fit properly. Here’s an example of one of the premade plans:
You can click the walls and change them, add and delete furniture, etc. I can’t explain it all fully, so I suggest you try it out.