I am looking for a replacement for the old TSS HTML add-on which is not supported with current Firefox versions.
It would save a link to all open tabs and a screen image for them - and then create an HTML page with that date. The web page could be stored to any location. When the page was later opened, it would give the option to click each individual prior tab to open or open them all (thus recreating your session). This was very useful for taking a break from doing research, etc. Link to the original add-on:
https://addons.mozilla.org/en-US/firefox/addon/tab-set-saver/
FoxyTab from erosman (https://addons.mozilla.org/en-US/firefox/user/azbb/) comes very close to doing this in individual pieces/functions.