Artifacts for a rhetorical analysis can come in many forms. Here are a few suggestions:
Artifacts should not have a a single, clear meaning, but be open to interpretation. A good artifact addresses a certain problem, and encourages a specific action to change the situation.
Context
What was the political/social/cultural climate in which your artifact was created? How does it relate to the intention of the artifact you are analyzing?
Resources for finding context:
People
Who are the relevant people related to your artifact? These may include the author, as well as specific groups or people mentioned in the artifact.
Resources for biographical information:
Outcomes
What are the relevant statistics related to your artifact? How have others reacted to the artifact, within the popular media, or scholarly studies?
Resources for finding outcomes: