Unsurprisingly for the former crafter main needing to put those skills back to the grindstone: extra materials can never go wrong, but tools for delicate metalwork/machining that she doesn't already have are very much also needed.

...Or just get her some steampunk-ass custom tailored men's clothing, that's probably easier.

(These are the things she'll mention out of necessity if asked directly, though she'll also comment that it's rather needless for anyone to bother with gifts for her. Observant people might notice that her hair still looks kind of rough (she can't make it perfect and then put it in time stasis anymore lol), and that she's uniquely terrible at feeding herself. There is No food in that clock tower. Maybe some drinks. Maybe she's a cafe regular for more reasons than just bothering Dipper...)