Description                               Code           Entity name   
===================================       ===========    =============
quotation mark                            "  -> "    "   -> "
ampersand                                 &  -> &    &    -> &
less-than sign                            <  -> <    <     -> <
greater-than sign                         >  -> >    >     -> >
Description                          Char Code           Entity name   
===================================  ==== ===========    =============
non-breaking space                          ->          ->  
inverted exclamation mark            ¡    ¡ -> ¡    ¡  -> ¡
cent sign                            ¢    ¢ -> ¢    ¢   -> ¢
pound sign                           £    £ -> £    £  -> £
currency sign                        ¤    ¤ -> ¤    ¤ -> ¤
yen sign                             ¥    ¥ -> ¥    ¥    -> ¥
broken vertical bar                  ¦    ¦ -> ¦    ¦ -> ¦
                                                         &brkbar; -> &brkbar;
section sign                         §    § -> §    §   -> §
spacing diaresis                     ¨    ¨ -> ¨    ¨    -> ¨
copyright sign                       ©    © -> ©    ©   -> ©
feminine ordinal indicator           ª    ª -> ª    ª   -> ª
angle quotation mark, left           «    « -> «    «  -> «
negation sign                        ¬    ¬ -> ¬    ¬    -> ¬
soft hyphen                              ­ ->     ­    -> 
circled R registered sign            ®    ® -> ®    ®    -> ®
spacing macron                       ¯    ¯ -> ¯    &hibar;  -> &hibar;
degree sign                          °    ° -> °    °    -> °
plus-or-minus sign                   ±    ± -> ±    ± -> ±
superscript 2                        ²    ² -> ²    ²   -> ²
superscript 3                        ³    ³ -> ³    ³   -> ³
spacing acute                        ´    ´ -> ´    ´  -> ´
micro sign                           µ    µ -> µ    µ  -> µ
paragraph sign                       ¶    ¶ -> ¶    ¶   -> ¶
middle dot                           ·    · -> ·    · -> ·
spacing cedilla                      ¸    ¸ -> ¸    ¸  -> ¸
superscript 1                        ¹    ¹ -> ¹    ¹   -> ¹
masculine ordinal indicator          º    º -> º    º   -> º
angle quotation mark, right          »    » -> »    »  -> »
fraction 1/4                         ¼    ¼ -> ¼    ¼ -> ¼
fraction 1/2                         ½    ½ -> ½    ½ -> ½
fraction 3/4                         ¾    ¾ -> ¾    ¾ -> ¾
inverted question mark               ¿    ¿ -> ¿    ¿ -> ¿
capital A, grave accent              À    À -> À    À -> À
capital A, acute accent              Á    Á -> Á    Á -> Á
capital A, circumflex accent         Â    Â -> Â    Â  -> Â
capital A, tilde                     Ã    Ã -> Ã    Ã -> Ã
capital A, dieresis or umlaut mark   Ä    Ä -> Ä    Ä   -> Ä
capital A, ring                      Å    Å -> Å    Å  -> Å
capital AE diphthong (ligature)      Æ    Æ -> Æ    Æ  -> Æ
capital C, cedilla                   Ç    Ç -> Ç    Ç -> Ç
capital E, grave accent              È    È -> È    È -> È
capital E, acute accent              É    É -> É    É -> É
capital E, circumflex accent         Ê    Ê -> Ê    Ê  -> Ê
capital E, dieresis or umlaut mark   Ë    Ë -> Ë    Ë   -> Ë
capital I, grave accent              Ì    Ì -> Ì    Ì -> Ì
capital I, acute accent              Í    Í -> Í    Í -> Í
capital I, circumflex accent         Î    Î -> Î    Î  -> Î
capital I, dieresis or umlaut mark   Ï    Ï -> Ï    Ï   -> Ï
capital Eth, Icelandic               Ð    Ð -> Ð    Ð    -> Ð
                                                         Đ -> Đ
capital N, tilde                     Ñ    Ñ -> Ñ    Ñ -> Ñ
capital O, grave accent              Ò    Ò -> Ò    Ò -> Ò
capital O, acute accent              Ó    Ó -> Ó    Ó -> Ó
capital O, circumflex accent         Ô    Ô -> Ô    Ô  -> Ô
capital O, tilde                     Õ    Õ -> Õ    Õ -> Õ
capital O, dieresis or umlaut mark   Ö    Ö -> Ö    Ö   -> Ö
multiplication sign                  ×    × -> ×    ×  -> ×
capital O, slash                     Ø    Ø -> Ø    Ø -> Ø
capital U, grave accent              Ù    Ù -> Ù    Ù -> Ù
capital U, acute accent              Ú    Ú -> Ú    Ú -> Ú
capital U, circumflex accent         Û    Û -> Û    Û  -> Û
capital U, dieresis or umlaut mark   Ü    Ü -> Ü    Ü   -> Ü
capital Y, acute accent              Ý    Ý -> Ý    Ý -> Ý
capital THORN, Icelandic             Þ    Þ -> Þ    Þ  -> Þ
small sharp s, German (sz ligature)  ß    ß -> ß    ß  -> ß
small a, grave accent                à    à -> à    à -> à
small a, acute accent                á    á -> á    á -> á
small a, circumflex accent           â    â -> â    â  -> â
small a, tilde                       ã    ã -> ã    ã -> ã
small a, dieresis or umlaut mark     ä    ä -> ä    ä   -> ä
small a, ring                        å    å -> å    å  -> å
small ae diphthong (ligature)        æ    æ -> æ    æ  -> æ
small c, cedilla                     ç    ç -> ç    ç -> ç
small e, grave accent                è    è -> è    è -> è
small e, acute accent                é    é -> é    é -> é
small e, circumflex accent           ê    ê -> ê    ê  -> ê
small e, dieresis or umlaut mark     ë    ë -> ë    ë   -> ë
small i, grave accent                ì    ì -> ì    ì -> ì
small i, acute accent                í    í -> í    í -> í
small i, circumflex accent           î    î -> î    î  -> î
small i, dieresis or umlaut mark     ï    ï -> ï    ï   -> ï
small eth, Icelandic                 ð    ð -> ð    ð    -> ð
small n, tilde                       ñ    ñ -> ñ    ñ -> ñ
small o, grave accent                ò    ò -> ò    ò -> ò
small o, acute accent                ó    ó -> ó    ó -> ó
small o, circumflex accent           ô    ô -> ô    ô  -> ô
small o, tilde                       õ    õ -> õ    õ -> õ
small o, dieresis or umlaut mark     ö    ö -> ö    ö   -> ö
division sign                        ÷    ÷ -> ÷    ÷ -> ÷
small o, slash                       ø    ø -> ø    ø -> ø
small u, grave accent                ù    ù -> ù    ù -> ù
small u, acute accent                ú    ú -> ú    ú -> ú
small u, circumflex accent           û    û -> û    û  -> û
small u, dieresis or umlaut mark     ü    ü -> ü    ü   -> ü
small y, acute accent                ý    ý -> ý    ý -> ý
small thorn, Icelandic               þ    þ -> þ    þ  -> þ
small y, dieresis or umlaut mark     ÿ    ÿ -> ÿ    ÿ   -> ÿ
&brkbar; and Đ
seem to be unique to HTF.
There is a list on
Entities
representing particular graphic characters with special meanings in HTML
and a list on the
ISO Latin 1 Entities in HTML
made available by the folks at CERN
(derived from ISO 8879).
[These seem to the ones currently known by Mosaic 2.4 for X.]
Or look at the end of
Appendix I
of CERN's
HTML+ Discussion Document
for another list of the mnemonic character entities for 8 bit ANSI Latin-1.
The
Appendix II
contains a
table
of the proposed character entities for HTML+ and their corresponding
character codes for Unicode and the Adobe Latin-1 & Symbol character sets.
Maybe also of interest to you is the
ISO 8859-1 FAQ
by Michael Gschwind (mike@vlsivie.tuwien.ac.at).
And I found a
table over the compose combinations
for X11R5 on SunOS systems (also available
with entities
where possible).
 It's taken from the MIT X sources in
server/ddx/sun/Compose.list.
Finally you could have a look at RFC 1345: Character Mnemonics & Character Sets by K. Simonsen (06/11/92, 103 pages, approx. 240 kbyte).