Are there any forms for a subpoena duces tecum that I could find?
Not sure about Washington, but in most jurisdictions only an attorney may issue a subpoena. There are all sorts of forms available on line and in form books and software. But, before an attorney issues a subpoena, the rules of the court in which the case is pending are reviewed, and these rules do vary from state to state and court to court. Sorry, I know this is not the answer you are looking for. This answer is offered for informational purposes only. It is not offered as, and does not constitute, legal advice. Laws vary widely from state to state. You should rely only on the advice given to you during a personal consultation by a local attorney who is thoroughly familiar with state laws and the area of practice in which your concern lies.