This code system http://hl7.org/fhir/assert-response-code-types defines the following codes:

CodeDisplayDefinition
continue ContinueResponse code is 100.
switchingProtocols Switching ProtocolsResponse code is 101.
okay OKResponse code is 200.
created CreatedResponse code is 201.
accepted AcceptedResponse code is 202.
nonAuthoritativeInformation Non-Authoritative InformationResponse code is 203.
noContent No ContentResponse code is 204.
resetContent Reset ContentResponse code is 205.
partialContent Partial ContentResponse code is 206.
multipleChoices Multiple ChoicesResponse code is 300.
movedPermanently Moved PermanentlyResponse code is 301.
found FoundResponse code is 302.
seeOther See OtherResponse code is 303.
notModified Not ModifiedResponse code is 304.
useProxy Use ProxyResponse code is 305.
temporaryRedirect Temporary RedirectResponse code is 307.
permanentRedirect Permanent RedirectResponse code is 308.
badRequest Bad RequestResponse code is 400.
unauthorized UnauthorizedResponse code is 401.
paymentRequired Payment RequiredResponse code is 402.
forbidden ForbiddenResponse code is 403.
notFound Not FoundResponse code is 404.
methodNotAllowed Method Not AllowedResponse code is 405.
notAcceptable Not AcceptableResponse code is 406.
proxyAuthenticationRequired Proxy Authentication RequiredResponse code is 407.
requestTimeout Request TimeoutResponse code is 408.
conflict ConflictResponse code is 409.
gone GoneResponse code is 410.
lengthRequired Length RequiredResponse code is 411.
preconditionFailed Precondition FailedResponse code is 412.
contentTooLarge Content Too LargeResponse code is 413.
uriTooLong URI Too LongResponse code is 414.
unsupportedMediaType Unsupported Media TypeResponse code is 415.
rangeNotSatisfiable Range Not SatisfiableResponse code is 416.
expectationFailed Expectation FailedResponse code is 417.
misdirectedRequest Misdirected RequestResponse code is 421.
unprocessableContent Unprocessable ContentResponse code is 422.
upgradeRequired Upgrade RequiredResponse code is 426.
internalServerError Internal Server ErrorResponse code is 500.
notImplemented Not ImplementedResponse code is 501.
badGateway Bad GatewayResponse code is 502.
serviceUnavailable Service UnavailableResponse code is 503.
gatewayTimeout Gateway TimeoutResponse code is 504.
httpVersionNotSupported HTTP Version Not SupportedResponse code is 505.
<status value="active"/><experimental value="false"/><date value="2021-01-05T10:01:24+11:00"/><publisher value="HL7 (FHIR Project)"/><contact><telecom><system value="url"/><value value="http://hl7.org/fhir"/></telecom><telecom><system value="email"/><value value="fhir@lists.hl7.org"/></telecom></contact><description value="The type of response code to use for assertion."/><jurisdiction><coding><system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/><code value="001"/><display value="World"/></coding></jurisdiction><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/assert-response-code-types"/><content value="complete"/><concept><code value="continue"/><display value="Continue"/><definition value="Response code is 100."/></concept><concept><code value="switchingProtocols"/><display value="Switching Protocols"/><definition value="Response code is 101."/></concept><concept><code value="okay"/><display value="OK"/><definition value="Response code is 200."/></concept><concept><code value="created"/><display value="Created"/><definition value="Response code is 201."/></concept><concept><code value="accepted"/><display value="Accepted"/><definition value="Response code is 202."/></concept><concept><code value="nonAuthoritativeInformation"/><display value="Non-Authoritative Information"/><definition value="Response code is 203."/></concept><concept><code value="noContent"/><display value="No Content"/><definition value="Response code is 204."/></concept><concept><code value="resetContent"/><display value="Reset Content"/><definition value="Response code is 205."/></concept><concept><code value="partialContent"/><display value="Partial Content"/><definition value="Response code is 206."/></concept><concept><code value="multipleChoices"/><display value="Multiple Choices"/><definition value="Response code is 300."/></concept><concept><code value="movedPermanently"/><display value="Moved Permanently"/><definition value="Response code is 301."/></concept><concept><code value="found"/><display value="Found"/><definition value="Response code is 302."/></concept><concept><code value="seeOther"/><display value="See Other"/><definition value="Response code is 303."/></concept><concept><code value="notModified"/><display value="Not Modified"/><definition value="Response code is 304."/></concept><concept><code value="useProxy"/><display value="Use Proxy"/><definition value="Response code is 305."/></concept><concept><code value="temporaryRedirect"/><display value="Temporary Redirect"/><definition value="Response code is 307."/></concept><concept><code value="permanentRedirect"/><display value="Permanent Redirect"/><definition value="Response code is 308."/></concept><concept><code value="badRequest"/><display value="Bad Request"/><definition value="Response code is 400."/></concept><concept><code value="unauthorized"/><display value="Unauthorized"/><definition value="Response code is 401."/></concept><concept><code value="paymentRequired"/><display value="Payment Required"/><definition value="Response code is 402."/></concept><concept><code value="forbidden"/><display value="Forbidden"/><definition value="Response code is 403."/></concept><concept><code value="notFound"/><display value="Not Found"/><definition value="Response code is 404."/></concept><concept><code value="methodNotAllowed"/><display value="Method Not Allowed"/><definition value="Response code is 405."/></concept><concept><code value="notAcceptable"/><display value="Not Acceptable"/><definition value="Response code is 406."/></concept><concept><code value="proxyAuthenticationRequired"/><display value="Proxy Authentication Required"/><definition value="Response code is 407."/></concept><concept><code value="requestTimeout"/><display value="Request Timeout"/><definition value="Response code is 408."/></concept><concept><code value="conflict"/><display value="Conflict"/><definition value="Response code is 409."/></concept><concept><code value="gone"/><display value="Gone"/><definition value="Response code is 410."/></concept><concept><code value="lengthRequired"/><display value="Length Required"/><definition value="Response code is 411."/></concept><concept><code value="preconditionFailed"/><display value="Precondition Failed"/><definition value="Response code is 412."/></concept><concept><code value="contentTooLarge"/><display value="Content Too Large"/><definition value="Response code is 413."/></concept><concept><code value="uriTooLong"/><display value="URI Too Long"/><definition value="Response code is 414."/></concept><concept><code value="unsupportedMediaType"/><display value="Unsupported Media Type"/><definition value="Response code is 415."/></concept><concept><code value="rangeNotSatisfiable"/><display value="Range Not Satisfiable"/><definition value="Response code is 416."/></concept><concept><code value="expectationFailed"/><display value="Expectation Failed"/><definition value="Response code is 417."/></concept><concept><code value="misdirectedRequest"/><display value="Misdirected Request"/><definition value="Response code is 421."/></concept><concept><code value="unprocessableContent"/><display value="Unprocessable Content"/><definition value="Response code is 422."/></concept><concept><code value="upgradeRequired"/><display value="Upgrade Required"/><definition value="Response code is 426."/></concept><concept><code value="internalServerError"/><display value="Internal Server Error"/><definition value="Response code is 500."/></concept><concept><code value="notImplemented"/><display value="Not Implemented"/><definition value="Response code is 501."/></concept><concept><code value="badGateway"/><display value="Bad Gateway"/><definition value="Response code is 502."/></concept><concept><code value="serviceUnavailable"/><display value="Service Unavailable"/><definition value="Response code is 503."/></concept><concept><code value="gatewayTimeout"/><display value="Gateway Timeout"/><definition value="Response code is 504."/></concept><concept><code value="httpVersionNotSupported"/><display value="HTTP Version Not Supported"/><definition value="Response code is 505."/></concept></CodeSystem>