Formfill by Joseph Karanja

Click the toolbar icon and every field on the page gets plausible fake data: names, emails, phone numbers, dates, passwords, select options, checkboxes and rich text editors.

File inputs are filled too. Add files once in settings and Formfill attaches them on every page that asks for an upload.

Field rules let you pin a pattern to a type or skip it. Optionally, text already on your clipboard is used for fields it matches.

Nothing is sent anywhere. There is no server and no analytics.