Dang these are much more useful than my first port of call for looking up http codes... which is http.cat/<code>. It's a shame you have to know what a code is to get to it... e.g. /404-not-found works instead of /404
https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/...
You don't need to know the name. You can increment the URL directly as well