No suggestions really ....... but I do endorse the hesitancy towards buying her things, as we all have our favourites, or that we want to personally choose any additions to our supplies.
I'm not a fan of giving gift cards, but sometimes they are more appropriate, in that in a case like this, it can be given, with a personal note as to the reason for the gift, and why the giver is leaving the selection up to the recipient.
However, gift cards can backfire ..... I was given one last Christmas and have not spent it yet.
It was for an online store that both of us had purchased from in the past with good response.
Meanwhile they have changed their shipping polices (from free to full charge), a discouraging factor!
Plus, every time I try to find a fabric I want to order, they don't have it.
Makes me even more hesitant on giving gift cards.