I'm right handed so inevitably the right glove wears out faster than the left. What, if anything, can I do with the left glove? I'd appreciate any good frugal ideas to make use of these.
I just use duct tape on the worn spots on the right hand glove until the left one wears out.
Find a left-handed gardener, and trade gloves.
Have you tried turning them inside out? The right becomes left, and left right. I often use the duct tape as well. Another trick is to duct tape your bare finger/s that are exposed with the hole/s. Oftentimes, depending on the task, I wear Costco nitrile gloves under cloth gloves. The cloth outer gloves seem to last longer, and the loose soil does not penetrate to skin. I reuse the nitrile gloves until they disintegrate.
If I have time, I mend/patch the holes in cloth/leather gloves with two layers, from an old glove-or even a piece of denim. This is not difficult with a half inch dowel in the finger space and using a curved 2 1/2"-3" upholstery needle. Like many here, I assume, my gloves do not always match.
If you must, you can decorate with embroidery! Have fun.