You can not go wrong giving an artist art supplies or gift certificates to art supply stores. Even if you give us something that is not our medium we will find a way to use it or play with it.
A gift certificate though, that's a beautiful thing. You can't buy groceries or shoes for the kids at the art supply store. What you can get is that item that you have talked yourself out of. "I can make do with what I've got."
In my case, that item was a drafting table.
I had one years ago from my high school days that I toted around from apartment to apartment. I was mostly painting then and didn't use it enough to justify moving it again, this time to another state. So I gave it away.
I didn't really miss it. I was still living in small apartments and focused only on painting.
My old drawing board from college, propped up on a box worked fine when I needed it.
Flash forward to the past few years. I live in a house with an actual art studio and illustration is back on my radar.
I still didn't think I needed the table but then I had a birthday.
And then I had a gift card.
And now I have a drafting table.