I am reposting two armory articles by Lothar von Katzenellenbogen (mka Thomas Barnes) which I think are interesting and useful: Authentic Heraldry Made Simple and A Critique and Ranking of Charges Found in the “Pictorial Dictionary of Heraldry As Used in SCA”.
They were written in the 1990s and archived at the Academy of Saint Gabriel, but were only available in a plain-text format that wasn’t very readable — the versions I’ve posted have had modern web styling applied to them and will hopefully be easier to scan.
These are over two decades old, and somewhat out of date, and they’re very opinionated, but they also contain some useful information, and I feel there’s value in them if they’re considered in context rather than taken as an authoritative reference.