Brooks seems to have the largest advertising budget, but there are plenty of other tensioned leather saddles on the market in 2019, with various design subtleties and features at different price points.

Berthoud - France
Brooks - UK
Gyes (Cardiff, Dia Compe, Fyxation, Lekker, Origin8, Papillionaire, Shinola, Spa, Torelli, Velo Orange, Zimbale, etc.) - Taiwan
Ideale - France
Lepper - Netherlands
Nasiruddin (Persons) - India
Rivet - AFAIK manufactured in Taiwan by Gyes but to their own proprietary designs
Sella Italia - Italy
Selle Anatomica - USA
Selle Monte Grappa - Italy
Tabor - Portugal