Usability.gov has a very comprehensive set of templates, forms, and examples that are organized by steps in the usability process: Plan, Analyze, Design, Test and Refine. They can be customized for your organization’s usability needs. All of these are in the public domain and can be freely downloaded.
Among the most useful of the files you’ll find in this collection are commonly used usability test plan templates, waivers and consent forms. I’ve used these forms many times in the past, and the examples provided can be easily modified to suit your needs.