Safety posters can cover a wide number of topics, including machine guards, eye protection, hearing protection, lifting, and food preparation. The Occupational Safety and Health Administration, or OSHA, offers a smaller collection of posters that can be ordered or printed out from .PDF files, according to OSHA's website.
There is a long list of posters that can be ordered from state level government services for a wide variety of safety topics. New York State Insurance Fund offers a number of safety posters that apply to various jobs and situations that contain national safety protocols and state level rules, as shown on its website. Each state provides posters that cover additional state regulations, which in some cases can be more specific then the national levels.