My Grandpa Elmer always used Linseed oil on his garden tool handles and I still have his hoe and shovel. I’m not as religious about doing it, and I usually wear gloves when using them, but if I see them looking shabby, I give them a treatment.
https://thejimbosliceworkshop.com/linseed-oil-for-woodworking-tool-handles/
Don’t ask me the brand, though. The bottle is in Beau’s ‘Catacomb of Missing Supplies’ in the ‘Silence of the Lambs’ basement, and I’m not going down there, LOL!
I have a favorite three-pronged, hand-held digger that was his, too. I painted the handle on that a bright TEAL BLUE that makes it easy to find again when I set it down...somewhere!
I use a block of bee’s wax on all my tool handles and in fact many of the metal shop tools.
The bee’s wax available as surplus from honey production is generously rubbed onto the handles and then gently warmed with a propane torch.
The result is a very good feel to your hands and complete weather proofing.
Ask a friendly bee keeper for a block of the wax and try it out. After just a few strokes, a rounded depression forms in the wax making application very easy