Here is he link to
all the FKK clubs in Germany ==>
http://www.travelsexguide.tv/germany.php/fkk/
Change "all" to "some" and you'd be right on. This does include most of the major clubs in Hessen and Artemis. It seems be be lacking the NRW clubs, PHG, GT, and Villa Vertigo, just to name a few. There are many more smaller clubs as well.
This list, which is 6 years old and possibly out of date, covers clubs in NRW only:
Amnesia, Castrop-Rauxel-Bladenhorst =>
http://castrop.mcfick.org/
Asia Sauna, Mönchengladbach =>
http://www.asia-sauna.de/
Asia Sexhaus, Moers =>
http://www.asia-sexhaus.de/
Asia Sexworld, Hilchenbach =>
http://www.asia-sexworld.de/
Bernds Sauna Club (Schieferhof), Hennef-Lichtenberg =>
http://www.bernds-sauna-club.de/
Casanova FKK, Vlotho =>
http://www.fkk-casanova.de/
Cleopatra Arena, Gelsenkirchen (neu) =>
http://www.cleopatra-arena.de/
Club 11. Etage (Pascha), Köln =>
http://www.11te-etage.com/
Club 1-2-3, Hagen =>
http://www.fkk-hagen.de/
Club Arabella, Bochum-Wattenscheid =>
http://www.arabella-fkk.de/
Club Belami, Dortmund-Dorstfeld =>
http://www.belami-fkk.de/
Club Globe, Leverkusen-Opladen/Fixheide (neu) =>
http://www.club-globe.de/
Club Grimberg Sauna, Gelsenkirchen =>
http://www.grimberg-fkk.de/
Club M., Rheinbach-Nord =>
http://www.club-manuela.de/
Club Sauna 2000, Marl =>
http://www.clubsauna2000.de/
Club Trauminsel, Reichshof =>
http://www.club-trauminsel.de/
Club Unique, Lomm bei Venlo / NL =>
http://www.sexclubunique.nl/
Club Villa Venus, Duisburg-Neumühl =>
http://www.venus-fkk.de/
Club Yin Yang, Roermond / NL =>
http://www.yinyang.nl/
De Limburgse Wallen, Maasbracht / NL =>
http://www.limburgsewallen.nl/
Dolce Vita Erotic-Lounge, Düsseldorf-Reisholz =>
http://www.city-fkk.de/
FKK Atlantica, Wuppertal-Varresbeck =>
http://www.fkk-atlantica.de/
FKK Club Relax, Dorsten =>
http://www.fkk-erotika.de/
FKK Pegasus, Wegberg-Wildenrath =>
http://www.fkk-pegasus.de/
FKK Saunaclub Great Palace, Gladbeck (neu) =>
http://www.fkk-greatpalace.de/
FKK Saunaclub Living Room, Kaarst-Holzbüttgen =>
http://www.fkk-living.de/
FKK-Club Pascha, Köln =>
http://www.pascha-fkk.de/
FKK-Club Penelope, Essen =>
http://www.clubpenelope.de/
FKK-Club Salome, Herne =>
http://www.fkksalome.de/
FKK-Club Samya, Köln-Rodenkirchen =>
http://www.samya.de/
FKK-Club Zeus, Wallenhorst =>
http://www.fkk-zeus.de/
FKK-Oase HeavensGate, Dorsten-Wulfen =>
http://www.fkk-heavensgate.com/
FKK-Sauna-Club Love Palace, Osnabrück =>
http://www.lovepalace-os.de/
FKK-Saunaclub Van Goch, Goch-West =>
http://www.fkk-vangoch.de/
Freude 39, Bochum =>
http://www.fkk-freudenberg.de/
FunGarden, Emmerich =>
http://www.fun-garden.com/
Haus Lug ins Land, Brachbach =>
http://www.clubluginsland.de/
Mausis Saunaclub, Dortmund-Aplerbeck =>
http://www.mausi-und-team.de/
new if club, Kamen =>
http://www.newifclub.de/
Parksauna Residenz, Lohmar-Durbusch =>
http://www.parksauna-residenz.de/
Parkschloss Dali, Marsberg-Bredelar =>
http://www.parkschlossdali.de/
Pauschal-Saunaclub Harem, Dormagen (neu) =>
http://www.harem-pauschalclub.de/
Planet Happy Garden, Tönisvorst =>
http://www.planet-happygarden.de/
Postillon Bar, Linne / NL =>
http://www.postillonbar.nl/
Privatclub Babylon, Elsdorf =>
http://www.babylon-privatclub.info/
Privatclub Neby, Dortmund-Marten =>
http://www.privatclub-neby.de/
Römerbad, Köln =>
http://www.roemerbad-cologne.de/
RTCs allgemein, Ruhrgebiet =>
http://www.saunaclubs-in-nrw.de/
Salon Rouge, Köln-Bickendorf =>
http://www.saunaclub-salonrouge.de/
Sauna Blue Note, Düsseldorf-Rath =>
http://www.saunabluenote.de/
Saunaclub 177, Bielefeld =>
http://www.saunaclub177.de/
Saunaclub Acapulco, Velbert-Röbbeck =>
http://www.fkkacapulco.de/
Saunaclub Atrium, Erkrath-Unterfeldhaus =>
http://www.saunaclub-atrium.de/
Saunaclub DejaVu, Melle-Westerhausen =>
http://www.saunaclub-dejavu.de/
Saunaclub Golden Gate, Münster =>
http://www.goldengatemuenster.de/
Saunaclub GoldenTime, Brüggen =>
http://www.goldentime.de/
Saunaclub Harem, Bad Lippspringe =>
http://www.saunaclubharem.de/
Saunaclub Lekker Ding, Wegberg-Wildenrath (neu ab Januar 2010) =>
http://www.saunaclub-lekkerding.com/
Sauna-Club Opium, Köln-Marsdorf (neu) =>
http://www.sauna-club-opium.de/
Saunaclub Paradise, Neuss (neu) =>
http://www.saunaclub-paradise.de/
Saunaclub Paradiso, Pulheim =>
http://www.saunaclubparadiso.de/
Sauna-Exclusiv, Hamm =>
http://www.sauna-exclusiv.de/
Süder Sauna Club, Recklinghausen-Süd =>
http://www.sauna-club-as.de/
Villa Erotika, Iserlohn-Dröschede =>
http://www.villa-erotika.com/
Villa Exclusive, Greven =>
http://www.villa-exclusive.de/
Villa Marisol, Hamminkeln =>
http://www.villa-marisol.de/
Villa Romantika, Recklinghausen =>
http://www.fkk-romantika.de/
Villa Silvana, Warstein (neu) =>
http://www.villa-silvana.com/
Villa Vertigo, Grefrath =>
http://www.villavertigo.de/
Waldsauna Gut Michelshohn, Hennef-Michelshohn (neu) =>
http://www.waldsauna-michelshohn.de/