I'm not sure I can provide a comprehensive list. Some obvious ones are a publication schedule, which needs to conform with the Freedom of Information Act obligations to publish information (irrespective of whether any request is received), a disciplinary policy and grievance policy in relation to employees (assuming a council has a clerk). It's a good idea to also publish the clerk's job description.
Policy statements need to be accessible to members of the public without undue difficulty by whatever means are available. That could include requests to the clerk, the local library, the council's web site.