We have a number of icons that are from the official NFPA 170 Standard for Fire Safety and Emergency Symbols.
You can see this symbols when you add elements to the map, of when you choose to add icons to images.
We also periodically add more icons at the request of our users!
Here are some of the icons
Access
Alarm
Confined Space
Drain
Fire Department Connection
Hazardous Materials
SiteDetail
Shutoff
Icons Available in the Photo Editor
There are lots of icons you can add to your images. See more details in this companion Help Article: