So I've been thinking vegapunk could be the founder of SWORD, or at least a founding member.
If I were to assume that SWORD was founded around the same time as the revolutionary army after the events of ohara, based off last chapter I would assume that sword would be made up of those "reasonable people" from the navy who vegapunk mentioned in his discussion with Dragon.
I would assume that Garp would have been one of the first people vegapunk spoke to after he declined the role of fleet admiral simply because of his dislike for the celestial dragons and world government, another big name that comes to mind would be aokiji, although he may not have been a founding member because he was still a part of the destruction of ohara,, that could have been the turning point for him. When he started to question the orders of the world government. I also don't think aokiji would honestly want to join someone like blackbeard, in my opinion he's probably a sword spy who's infiltrated bbs crew the way drake did with Kaido.