Forgive me, but it seems you have been given several nice, generic suggestions that would work in your case (gift card, picture frame, wine, even nothing at all)
Are you wanting instead to talk about your sister who you aren't close to, who drains you emotionally, who is likely to change her date, etc., etc.,???
Because among all the nice, general wedding gift suggestions (as requested in your original post) your only responses seem to me like a fishing expedition.
Would you rather vent about your sister??? It's okay if that's what you want. But why mask it as "looking for gift suggestions"?