A fairly comprehensive list of available fields in endnote and conversions to bibtex. 
Note:
* This was made by combining the fields available to @misc, @article and @inproceedings entries, so anything that endnote thinks should only be mapped for the other entries won't be here.
* Some of the bibtex fields are built from different endnote fields (and vice versa) depending on the  entry type (e.g. the endnote date field may map to month or year, the bibtex year field may come from year or year of conference, the bibtex journal field may come from journal or secondary title.


   `Author = {`Author`},`
   `Title = {`Title`},`
   `BookTitle = {`Conference Name`},`
   `Editor = {`Editor`},`
   `Series= {`Series Title`},`
   `Address= {`Conference Location`},`
   `Year = {`|Year of Conference|`},`
   `SeriesEditor= {`Series Editor`},`
   `Publisher = {`Publisher`},`
   `Volume = {`Volume`},`
   `Number = {`Number`},`
   `Pages = {`Pages`},`
   `Date = {`Date`},`
   `Note = {`Notes`},`
   `Abstract = {`Abstract`},`
   `Keywords = {`Keywords`},`
   `ISBN = {`ISBN/ISSN`},`
   `Journal = {`Journal`},`
   `Issue = {`Issue`},`
   `AlternateJournal = {`Alternate Journal`},`
   `SecondaryAuthor = {`Secondary Author`},`
   `SecondaryTitle = {`Secondary Title`},`
   `PlacePublished = {`Place Published`},`
   `NumberOfVolumes = {`Number of Volumes`},`
   `Section = {`Section`},`
   `TertiaryAuthor = {`Tertiary Author`},`
   `TertiaryTitle = {`Tertiary Title`},`
   `Edition = {`Edition`},`
   `TypeOfWork = {`Type of Work`},`
   `SubsidiaryAuthor = {`Subsidiary Author`},`
   `ShortTitle = {`Short Title`},`
   `AlternateTitle = {`Alternate Title`},`
   `OriginalPublication = {`Original Publication`},`
   `ReprintEdition = {`Reprint Edition`},`
   `ReviewedItem = {`Reviewed Item`},`
   `Custom1 = {`Custom 1`},`
   `Custom2 = {`Custom 2`},`
   `Custom3 = {`Custom 3`},`
   `Custom4 = {`Custom 4`},`
   `Custom5 = {`Custom 5`},`
   `Custom6 = {`Custom 6`},`
   `AccessionNumber = {`Accession Number`},`
   `CallNumber = {`Call Number`},`
   `URL = {`URL`},`
   `AuthorAddress = {`Author Address`},`
   `Date = {`Date`},`