Just a few:
Richard Avedon (w/150mm lens when he wanted to get closer than the RolleiflexTLR allowed); Bert Stern, Helmut Newton, Diane Arbus, Viktor Skrebneski, Irving Penn, Steven Meisel, Francesco Scavullo, Annie Leibowitz, Anton Corbijn, Patrick Demarchelier, Karl Lagerfeld (the designer), Nigel Parry, Michel Comte, Mark Tucker (
www.marktucker.com).... Most of these use the Hassy along with other cameras, or have used it at one significant point in their careers. They may or may not be known more for use of other cameras.
Most of the above are 'fashion-related.' In the fine-art arena, many would be less well-known. You can find some wonderful photographers at:
http://www.photoeye.com/gallery/PhotoShowcase/homepagePSNew.cfm
For Hasselblad use, look for square compositions, and, as noted above, the two triangular notches in the left frame border. They are also, rarely, found on the right frame, if the picture has been flopped. My favorite on the photo-eye site is Hiroshi Watanabe - especially the portraits.
You can also visit the Hasselblad website. There is a MASTERS section and a magazine section which profiles a photographer each month. You'll find some well-known people as well as less-known, regional photographers there.
Hope this helps, but i'm still sorta curious as to how....