I have been a fan of an accessory thumb rest for digital cameras ever since Tim Isaac of Matchtechnical produced his first model for the digital Leica bodies back in 2007. My preference is born of long use of film cameras, with my thumb hooked around the wind-on lever to aid stability and handling.  The first digital cameras lacked that protrusion, of course, and their handling suffered as a result, reaching a nadir in the defiantly unergonomic Leica M8. Today, eBay and Amazon are flooded with the things but, as I have said on many an occasion in the past, buy cheap, buy twice. I have tried a couple of the cheapies over the years and just like lens adaptors, the bottom end of the market is full of ill-fitting, badly made cheap copies of the better products. I chanced upon Lensmate a couple of years ago. This Seattle-based company was first formed in 1998. They started out small, producing adaptor tubes to allow filters to be fitted to cameras with no filter thread. Today they fabricate and market a range of accessories, predominantly for Fuji, Sony, Panasonic and Canon mirrorless cameras…….

Source: Fuji X-Pro2: Lensmate thumb rest and soft release transform handling — macfilos

Bill Palmer Lensmate Lensmate thumb rest LM-XP2 Thumbrest