Link Gopher is an add-on for Firefox: it extracts all links from web page, sorts them, removes duplicates, and displays them in a new tab for inspection or copy and paste into other systems.
To download and install the latest release of Link Gopher: https://addons.mozilla.org/en-us/firefox/addon/link-gopher/
Link Gopher home page https://sites.google.com/site/linkgopher/Home