Wikimedia Commons has media related to PD license tags.

The pages listed in this category are templates. This page is part of Wikipedia's administration and not part of the encyclopedia. Further template category notes This category contains pages in the template namespace. It should not be used to categorize articles or pages in other namespaces. To add a template to this category: If the template has a separate documentation page (usually called "Template:template name/doc"), add  [[Category:Public domain copyright templates]] to the <includeonly> section at the bottom of that page. Otherwise, add  <noinclude>[[Category:Public domain copyright templates]]</noinclude> to the end of the template code, making sure it starts on the same line as the code's last character.

The majority of the templates shown here are for tagging files. For giving attribution in an article, you can use ((PD-notice)) or use any of the more specific templates in Category:Attribution templates.