Here’s a useful list I made in 2011 of all sorts of style guides accessible online to help make your writing consistent and more easily understood.
I thought I would revisit it as a United States reader of this blog recently found a broken link to the NASA grammar and punctuation guide I had listed, and very kindly sent me a working link. Thanks, Liz!
That pushed me to check all the links and update them where needed. So … a very useful page and fresh links: Fill your boots!