It’s really a matter of personal taste; that’s why it’s not in the docs. Your feelings on what best represents a light switch and mine may vary quite a bit. For example, you may consider a car icon perfect for your garage where I may use the garage icon.
If you’d like a starting point for something like weather, I listed the icons I used in this post:
But again, these are choices I made based on what I thought was a good representation of these specific sensors and you may or may not agree.