Primary Twine story formats can be downloaded with this link, or with this one. Here is another download link.
And of course I must link to the three most important resources (ChapelR's Tweego, Chris Klimas' Twine, and Visual Studio Code. These are bundled together and can be downloaded here and here and here.
Hiev's browser storage tool is a must-have. The same author produced a nice collection of sample code, which I make downloadable here.
Here is Gwentastic's Twee File Splitter, and here is another download link. I've also backed it up to my OpenDrive and it's located here on my Onedrive account.
Finally, my go-to SugarCube template for getting new projects initiated.