This list includes items for HTTP, WebDAV and P3P. Grouped by "field" and ascending sorted, they are:
connect, copy, delete (HTTP), delete (WebDAV), get (HTTP), get (WebDAV), head (HTTP), head (WebDAV), lock, mkcol, move, options, post (HTTP), post (WebDAV), propfind, proppatch, put (HTTP), put (WebDAV), trace, unlock.
Accept, Accept-Charset, Accept-Encoding, Accept-Language, Accept-Ranges, Age, Allow, Authorization, Cache-Control, Connection, Content-Encoding, Content-Language, Content-Length, Content-Location, Content-MD5, Content-Range, Content-Type, DAV, Date, Depth, Destination, ETag, Expect, Expires, From, Host, If, If-Match, If-Modified-Since, If-None-Match, If-Range, If-Unmodified-Since, Keep-Alive, Last-Modified, Location, Lock-Token, Max-Forwards, Overwrite, P3P, Pragma, Proxy-Authenticate, Proxy-Authorization, Public, Range, Referer, Retry-After, Server, Status-URI, TE, Timeout, Trailer, Transfer-Encoding, Translate, Upgrade, User-Agent, Vary, Via, WWW-Authenticate, Warning.
100, 101, 102, 200, 201, 202, 203, 204, 205, 206, 207, 300, 301, 302, 303, 304, 305, 306, 307, 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 422, 423, 424, 500, 501, 502, 503, 504, 505, 507.