Ok, I will preface this by saying I know the general wisdom given here is no identical gifts. That being said, my wedding party all have very similar personalities and interests, and I think this will be something they would all think was really fun; I'm just trying to see if people think it's an okay exception/something people would actually like to have or it would just go in the closet after the wedding day/etc.
A bit of backgroun: because I don't have all women, my MOH, deciding we needed a gender-neutral term, came up with the idea that they were the "Bridescoats" (like the Firefly Browncoats, since all of us are huge nerds and love Firefly). I was thinking about getting sweatshirts that were sort of a play on that (see photo). I could also get each person one or two small, more personal items if people think this is fun but not personal enough?
Re: Gift feedback
Is there nothing else you can find them related to their interests that has nothing to do with your wedding? Even if you gave me a plain hoodie in my favorite color I'd probably wear it again. Save the themed joke for the card or gift tag and make the gift something genuinely for them unrelated to your wedding.
Like adk19, I love Dr. Who, but if you gave me a Dr. Who sweatshirt with some cutesy wedding thing on it, it would be going in the "donate" pile (except there is actually a shirt with the Tardis and that "something old, something new" saying from Amy's wedding episode. I'd wear that).
Not it so much the Bridecoats, though. I'd wear it for my friend's wedding related stuff, but be disappointed to get such an almost awesome sweatshirt I'd never wear out.