First off, despite my old age, I don't have a bucket list. Useless to me. I've lived a rather full life and while I haven't dun didded everything, oh well. Stuff happens. At least I've read about it.
As for bucket list objects, this question isn't exactly unique, so my answer is quite well rehearsed.
Everything. I am fascinated and love to see EVERY single object up there I find. It doesn't matter what it is. Quite often, it's a smudge I can barely see by jiggling the scope. An example is that I finally bagged Palomar 15 the last time I was out. That's one for the record books, at least mine. It was extremely faint and barely detectable.
Yet, it doesn't matter if it's a smudge of a showpiece, it fills the requirement for a supposed bucket list. It's a new object I've never seen before.
Good enough for guv'mint work.