Great Britain's endgame study supremo is John Roycroft, founder of EG – an important magazine of the genre
Alexander Rueb Vereniging voor SchaakEindspelStudie – a Dutch association for endgame study enthusiasts – now with a newly-refurbished website by Peter Boll.
A website created by John and Sue Beasley. It includes a PDF archive of the full run of British Endgame Study News (BESN) (which ran from 1996 to 2010), a new presentation of Reti's endgame studies and much other chess composition content. Non-chess content includes music and a remarkable diary of Moravian village life.
A website by Brian Gosling that seeks to expound the endgame in chess. To help with this it quotes lots of endgame studies.
I am happy to add more links to the above list. Please just let me know about them.
Developed and maintained by Brian Stephenson.
Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) &
CSS/Javascript (jQuery, Bootstrap & DataTables).