One of my all-time favorite golf-related products, the Bushnell Wingman bluetooth speaker & GPS unit is maybe the best/easiest gift I can recommend for a golf enthusiast - as long as they don't hate the concept of music on the course.
The most comfortable golf clothes I've worn, Redvanly is a premium golf brand with amazing materials and great looks.
For around $20, alignment aids can be a terrific stocking stuffer for the golfer in your life, or for you. Goodstick Golf has some of the game's best alignment sticks, featuring magnetic tops, pointed ends and a professional looking product that sits in your bag just shorter than a driver.
The best gift you never knew you needed: A Blue Tees rangefinder magnetic strap. Simply snap your rangefinder on to the metal bar of the cart frame and have easy access throughout your round - works on almost all brands and models!