Gifts I received as a BO/instructor/trainer that I loved:
Good gloves. No one who works outdoors ever has enough.
Good socks, boot socks and work socks. I had a pair of cashmere boot socks that were the best thing ever. Silk sock liners are lovely for under tall boots. Insulated socks for work boots are great too.
The chemical hand and boot warmer packets that you break open and shove in your boots or gloves. A student bought me a case of them for Christmas one year, and that was an awesome present. We went to an indoor winter show season that year, and I blessed that kid at every show as I stood in the cold.
A halter with a name plate, or one of the nylon ones with the name stitched in for her favorite horse. I never would spend the money on my own guys or the schoolies, but I coveted them.
Ditto brass nameplates for saddles and bridles. A bunch with the brass disc typ with the name of the farm would be good.
A photo collage or manip of her horses or the farm. I had kids and a boader do a couple of these for me and I cherished them. Even better was a blown up cartoon of a riding school with funny labels and comments on the horses and riders; that was from my show kids one year.
Gift cert to my favorite restaurant.
One hand gate latches.