Gift Ideas for a Cake Decorator

My sister decorates cakes as a hobby and I would like to give her a gift. She’s been at it for about two years now, so she has a lot of the basic stuff. She got a rather nice cake set last year (I don’t know what is in those beyond some sort of rotating tilting tray plate thing to assist with decorating). So I was just hoping you might have suggestions for a semi armature cake decorator. Just a few notes that might help

1) I don’t want to give her lessons. It’s sort of like saying I don’t think she’s good enough at it.
2) She seems to lean toward her cakes tasting good over form. Which is why she refuses to use fondant and uses some fancy icing from the arts and crafts store that costs a lot.
3) She mostly seems to use boxed cake mix you might find in the super market.
4) I believe she has most of the basic tools. But if there are any upgrades to the basics you think might make a difference, please let me know.

I don’t know how much cake decorating stuff costs, so I guess I’ll find out. Don’t let that stop suggestions. I apologize for my lack of knowledge on the subject. Any and all help is greatly appreciated. Thank you for taking the time to read my post.