I can give you a partial answer to that, but first I’d like to present some arguments against asking the question in the first place. As you’ve already noted, SenseTalk is highly contextual, so a word that has special meaning in one place is perfectly fine to use in other contexts. Also, there are well over a thousand words that have some kind of meaning in SenseTalk, which is a lot to try to avoid, and most will never conflict with your variable names. The list of restricted words you pointed to in the documentation is intentionally short and rarely changes, while the list of words with some sort of meaning grows regularly.
That being said, I understand the desire to see a more complete SenseTalk word list. For now, a comprehensive list doesn’t really exist, but buried inside the Eggplant application there is a file that comes close, with several caveats. The file is called SenseTalkKeywords.txt and is located in the Resources folder (the exact path depends on the platform — on Mac it is Eggplant.app/Contents/Resources/SenseTalkKeywords.txt). From its name you might think it is exactly what you’re asking for, but in fact its purpose is to provide a list of some of the terms that can be autocompleted in a script. The terms in this file omit a lot of things that would add more clutter than benefit in that context, including hundreds of unit names, so it’s not really comprehensive. But you may find it useful anyway.