For full reference... As far as i could get...
First - .htaccess formatted
Second - Descriptions.
All these i found here -> httpstatuses.com
These are All codes - Not just Errors
.. Some will break your site. .
Use like:
ErrorDocument 100 https://EXAMPLE.com
This is the exact copy Paste.. It is not mine, however i reformatted the list.
( Hover for description, Click for detail. )
1×× : Informational
• 100 : Continue
• 101 : Switching Protocols
• 102 : Processing
2×× : Success
• 200 : OK
• 201 : Created
• 202 : Accepted
• 203 : Non-Authoritative Information
• 204 : OK (No Content)
• 205 : Reset Content
• 206 : Partial Content
• 207 : Multi-Status
• 208 : Already Reported
• 226 : IM Used
3×× : Redirection
• 300 : Multiple Choices
• 301 : Moved Permanently
• 302 : Found
• 303 : See Other
• 304 : Not Modified
• 305 : Use Proxy
• 307 : Temporary Redirect
• 308 : Permanent Redirect
4×× : Client Error
• 400 : Bad Request
• 401 : Unauthorized
• 402 : Payment Required
• 403 : Forbidden
• 404 : Not Found
• 405 : Method Not Allowed
• 406 : Not Acceptable
• 407 : Proxy Authentication Required
• 408 : Request Timeout
• 409 : Conflict
• 410 : Gone
• 411 : Length Required
• 412 : Precondition Failed
• 413 : Request Entity Too Large
• 414 : Request-URI Too Long
• 415 : Unsupported Media Type
• 416 : Requested Range Not Satisfiable
• 417 : Expectation Failed
• 418 : I'm a teapot
• 422 : Unprocessable Entity
• 423 : Locked
• 424 : Method Failure
• 426 : Upgrade Required
• 428 : Precondition Required
• 429.") : Too Many Requests
• 431 : Request Header Fields Too Large
• 444 : No Response
• 451 : Unavailable For Legal Reasons
• 499 : Client Closed Request
5×× : Server Error
• 500 : Internal Server Error
• 501 : Not Implemented
• 502 : Bad Gateway
• 503 : Service Unavailable
• 504 : Gateway Timeout
• 505 : HTTP Version Not Supported
• 506 : Variant Also Negotiates
• 507 : Insufficient Storage
• 508 : Loop Detected
• 510 : Not Extended
• 511 : Network Authentication Required
• 599 : Network connect timeout error
(Source)