MUSEUMS & LIBRARIES:
The French Playing Card Museum in Issy-les-Moulinaux, a suburb of
Paris (also see: "Events").
The German Playing Card Museum in Leinfelden-Echterdingen, close to Frankfurt.
The Belgian National Playing Card Museum in Turnhout.
A Spanish Playing Card Museum in Oropesa del Mar, about 80 km from Valencia.
The Jean Dieudonné Playing Cards Museum in the Kulturhuef in
Grevenmacher, Luxembourg.
The virtual Speelkaartenmuseum about Dutch
playing cards.
The Cuban Museo de Naipes in Havana.
The Bibliothèque nationale de France. Enter "JeuCart"
to search or refine by adding keywords in French, e.g. "JeuCart+allemand"
for German playing cards.
CLUBS:
IPCS, International Playing Card Society.
52+Joker, American collectors club of old
playing cards.
L'Accart, the French playing card collectors
society.
EPCS, English Playing Card Society.
Asescoin, Facebook page of the Spanish club of playing card collectors.
7Bello, the Italian collectors website.
Asacon, the Argentine club of playing card collectors.
Talon, the Austrian Hungarian club of playing card collectors.
Bube - Dame - König, the German club of playing card collectors.
Melbourne Playing Cards Collectors Inc. (MPCC), the Australian club of playing card collectors.
COLLECTORS:
Peter Endebrock's site with extensive info on
taxstamps from all over the world.
Alexander Sukhorukov's World Wide Web Playing
Card Museum.
Paul Bostock is a long time collector and his interest
goes from old English packs to modern non-standard decks.
A Dutch SN jokers collector's site, with different
collectible backs too and links to other joker collectors.
Alta Carta, a Swiss founded trading site, supported by
different collectors.
The Coral Collection (a sub of CeDIG),
informative site containing major playing cards of the 20th century, European style.
White Knuckle Playing Cards, an Australian site with
info about early US manufacturers, games and more.
My Dear Playing Cards, a Spanish website by Manuel Gámez, with a large
collection of modern decks.
Klaus-Jürgen Schultz's website with a small but very interesting display of
antique German decks from his collection.
A Gallery of Standard English Playing Cards by Paul Bostock and Ken Lodge,
playing card historians and collectors.
"Kartenhaus", a site with a virtual playing card museum, maintained
by a Swiss collector Ernst Alder.
Gejus van Diggele is a Dutch collector of secondary used playing cards and
games related to WWII. He gives lectures and has traveling exhibitions about
these topics.
PubbliCartoMania, a site where Italian collector Toni Di Rossi shows his
collection.
Kevan "The Congress Guy" Seaney's site with a complete oversight of the
USPCC's Congress brand playing cards.
CARDMAKERS
HEARTS, a Dutch playing cards manufacturer.
PIATNIK from Vienna, Austria.
FRANCE-CARTES (now CARTAMUNDI FRANCE), a leading French manufacturer.
CARTAMUNDI, the world's largest manufacturer.
CIVERTAN, a manufacturer from Hungary.
The WORSHIPFUL COMPANY of Makers of Playing Cards
MISCELLANEOUS & BLOGS
The COLLECTORS WEEKLY, a US website for every kind of
collector and......... with a playing cards section!
"COLLECTOR" a blog showing different decks of playing cards.
Ken Lodge's blog, mainly about the Engish and American pattern, but with
non-standard decks too.
PRESS 
IN CASE OF NON-FUNCTIONING LINKS