All US Amazon links:
USB-C Rechargeable handwarmers: https://www.amazon.com/dp/B0BG9TB26K?
Photography mittons/gloves: https://www.amazon.com/dp/B081D7B54P?
For landscape/astro/night shooters - Lens warmers: https://www.amazon.com/gp/product/B07L1N9YBH/
For night/astro shooters - Headlamp: https://www.amazon.com/gp/product/B09C85T9HX/
For wildlife/fishermen/boat/adventure shooters - Cheap chest waiters: https://www.amazon.com/gp/product/B07JZBF17G/
For wildlife/birders - Small monocular (like binoculars, but only on optic, I love mine): https://www.amazon.com/gp/product/B004KMA19Y/
I love the gloves for cooler/milder weather. They're light and pack down nice when not in use. I like the hybrid design of them being mittens while still allowing your fingers full access to touch screens when not in "mitten mode". I never had an issue with the magnets, personally.
However, I wouldn't recommend these gloves for anything below the 40's F (4-5 C). I have a much more expensive/rugged pair for colder temps, but they're 4X the price, clunkier (harder to work with in the field) and take up twice the room in my bag when not in use.