Your footguns.org file legitimately sounds like something that other C++ programmers would find useful. I for one, being a rank novice at the language (despite attempting to use it for the last ten years!), would certainly appreciate a reference like that.
Most of it is basically from cppcon talks and Scott Meyer's books, but the advice I basically give to incoming C++ programmers today is this:
* Start with C++20 unless you have a very good reason not to. Not only does it obviate crufty old things like SFINAE (concepts!), but it includes a ton of usability fixes (e.g. reflexive operator== -> I only have to write the code for MyType == MyOtherType in order to get both that version and MyOtherType == MyType). A lot of lambda behavior has really been cleaned up too (e.g. capturing `this` has fewer corner cases).
* start with Google's coding guidelines [0], as they've been developed to avoid many footguns (the bottom line depends on it). Once you understand things better, keep removing these rules (e.g. about exceptions, const& parameters; many of these rules are good for big teams, but annoying to follow for individuals)
* The CppCon "back to basics" talks are absolute goldmines, and the speakers usually tell you if some technique has been outdated as of the recording. Some things in certain books, although valuable, may be outdated based on later revisions to the language.
* The best notes to take are usually some structure list followed by a bunch of godbolt links with examples, e.g. this one I made to demonstrate the reflexive operator== behavior [1]