The only keyboard shortcuts that should be available (and I'm ignoring Windows keyboard shortcuts that "work in every application, when the context for their use exists") is either from the software developer, and these are generally documented, your screen reader, or a script/add-on to your screen reader.
They also generally need to be web searched for as separate entities, e.g,, [Microsoft Word Keyboard Shortcuts] versus [JAWS Word keyboard shortcuts]. Stick whatever is appropriate, e.g., Quickbooks or Facebook App or Win10 Mail App, etc., for "Microsoft Word" and the principle still applies.
If you're looking for keyboard shortcuts for virtually anything Microsoft produces, using that above format in the web search engine of your choosing almost invariably turns up Microsoft's own page of those shortcuts somewhere in the first five results returned, and very often the first one. But since web search results in every search engine I've used are returned as headings, you can make quick work of reviewing the first few results and, if necessary, adjusting your search terms to either exclude certain words with the minus operator immediately before a term, e.g., -case, force inclusion of certain terms, e.g,, +font, or just adding some additional search terms to narrow down your results because you started with too few, and got a lot of garbage back as a result.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
There are many who labor under the gross misapprehension that the Constitution is a cage and a laundry-list rather than a framework upon which great things have been and still will be built. Many things that are entirely Constitutional are not "in the Constitution," but are allowed under it.