I know a number of our customers use a thumb rest on their pistols. In general, thumb rests promote a strong left-hand grip for right-hand shooters; it provides something extra to clamp on to. Thumb rests were popularized on the Sig Sauer P320, but have propagated across many pistols.
In the next week or two, Align Tactical will be launching their thumb rest for the Sig Sauer P365. I recently shot a pistol with this thumb rest, and this is what I thought
For this thumb rest, you’ll likely need to use a holster with the appropriate channel built in. Thankfully, Werkz does have holsters for the P365 X-Macro or Fuse versions with this thumb rest. Check them out here: