| 9694 | Guidelines for the Definition of New Top-Level Media TypesM.J. Dürst | Best Current Practice | March 2025 |
| 6709 | Design Considerations for Protocol ExtensionsB. Carpenter, B. Aboba, Ed., S. Cheshire | Informational | September 2012 |
| 5738 | IMAP Support for UTF-8P. Resnick, C. Newman · obsoleted by RFC 6855 | Experimental | March 2010 |
| 4185 | National and Local Characters for DNS Top Level Domain (TLD) NamesJ. Klensin | Informational | October 2005 |
| 2199 | Request for Comments Summary RFC Numbers 2100-2199A. Ramos | Informational | January 1998 |
| 2161 | A MIME Body Part for ODAH. Alvestrand | Experimental | January 1998 |
| 2112 | The MIME Multipart/Related Content-typeE. Levinson · obsoleted by RFC 2387 | Proposed Standard | March 1997 |
| 2049 | Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and ExamplesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2046 | Multipurpose Internet Mail Extensions (MIME) Part Two: Media TypesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 1896 | The text/enriched MIME Content-typeP. Resnick, A. Walker | Informational | February 1996 |
| 1849 | "Son of 1036": News Article Format and TransmissionH. Spencer · obsoleted by RFC 5536, RFC 5537 | Historic | March 2010 |
| 1614 | Network Access to Multimedia InformationC. Adie | Informational | May 1994 |
| 1599 | Summary of 1500-1599M. Kennedy | Informational | January 1997 |
| 1563 | The text/enriched MIME Content-typeN. Borenstein · obsoleted by RFC 1896 | Informational | January 1994 |
| 1523 | The text/enriched MIME Content-typeN. Borenstein · obsoleted by RFC 1563, RFC 1896 | Informational | September 1993 |
| 1521 | MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message BodiesN. Borenstein, N. Freed · obsoleted by RFC 2045, RFC 2046, RFC 2047, RFC 2048, RFC 2049 | Draft Standard | September 1993 |
| 1505 | Encoding Header Field for Internet MessagesA. Costanzo, D. Robinson, R. Ullmann | Experimental | August 1993 |
| 1496 | Rules for downgrading messages from X.400/88 to X.400/84 when MIME content-types are present in the messagesH. Alvestrand, J. Romaguera, K. Jordan | Historic | August 1993 |
| 1495 | Mapping between X.400 and RFC-822 Message BodiesH. Alvestrand, S. Kille, R. Miles, M. Rose, S. Thompson · obsoleted by RFC 2156 | Proposed Standard | August 1993 |
| 1494 | Equivalences between 1988 X.400 and RFC-822 Message BodiesH. Alvestrand, S. Thompson | Historic | August 1993 |
| 1486 | An Experiment in Remote PrintingM. Rose, C. Malamud · obsoleted by RFC 1528, RFC 1529 | Experimental | July 1993 |
| 1468 | Japanese Character Encoding for Internet MessagesJ. Murai, M. Crispin, E. van der Poel | Informational | June 1993 |
| 1456 | Conventions for Encoding the Vietnamese Language VISCII: VIetnamese Standard Code for Information Interchange VIQR: VIetnamese Quoted-Readable SpecificationVietnamese Standardization Working Group | Informational | May 1993 |
| 1440 | SIFT/UFT: Sender-Initiated/Unsolicited File TransferR. Troth | Experimental | July 1993 |
| 1437 | The Extension of MIME Content-Types to a New MediumN. Borenstein, M. Linimon | Informational | 1 April 1993 |
| 1428 | Transition of Internet Mail from Just-Send-8 to 8bit-SMTP/MIMEG. Vaudreuil | Informational | February 1993 |
| 1427 | SMTP Service Extension for Message Size DeclarationJ. Klensin, N. Freed, Ed., K. Moore · obsoleted by RFC 1653 | Proposed Standard | February 1993 |
| 1426 | SMTP Service Extension for 8bit-MIMEtransportJ. Klensin, N. Freed, Ed., M. Rose, E. Stefferud, D. Crocker · obsoleted by RFC 1652 | Proposed Standard | February 1993 |
| 1425 | SMTP Service ExtensionsJ. Klensin, N. Freed, Ed., M. Rose, E. Stefferud, D. Crocker · obsoleted by RFC 1651 | Proposed Standard | February 1993 |
| 1399 | Summary of 1300-1399J. Elliott | Informational | January 1997 |
| 1392 | Internet Users' GlossaryG. Malkin, T. LaQuey Parker · obsoleted by RFC 1983 | Informational | January 1993 |
| 1344 | Implications of MIME for Internet Mail GatewaysN. Borenstein | Informational | June 1992 |
| 1343 | A User Agent Configuration Mechanism for Multimedia Mail Format InformationN. Borenstein | Informational | June 1992 |
| 1342 | Representation of Non-ASCII Text in Internet Message HeadersK. Moore · obsoleted by RFC 1522 | Proposed Standard | June 1992 |
| 1340 | Assigned NumbersJ. Reynolds, J. Postel · obsoleted by RFC 1700 | Historic | July 1992 |