Brooks
Persons
Selle Anatomica
Berthoud
Gyes
Cardiff, made by Gyes
Velo Orange, made by Gyes
Zimbale, made by Gyes
Origin 8, made by Gyes
Tops
Lepper (out of business?)
Ideale - definitely out of business
Torelli
Dia Compe
Selle Monte Grappa
Spa
Papillionaire
Rivet

No connection to any retailers mentioned, examples only. There are plenty of places to get any of these.

(I suspect the Torelli, Dia Compe, Spa, Papillionaire and Rivet saddles are also manufactured to specification by Gyes.)