[techcode]

Those ...?

Would those be stuff like carpentry/construction, animal husbandry, distilling alcohol, making "green" petrol/diesel (from vegetables), cooking gas (from food scraps and manure) ...

And anything and everything else that might be considered long term and post fall of civilization prepping?

At that point you might as well also add knowledge of some Germanic (that includes English), Slavic and CJK/Asian language... Though French, Spanish, Portugese and such could also come in handy.