Can't say that I've ever been but I've recently heard of something called the Mid-Atlantic Sports Card Show located in Silver Spring, MD. Out of the blue I kept getting notifications for it on my FB feed.
With that said, looking at the pics on the website, I don't think it's very large so not sure what the pre-war/vintage scene looks like at this place.
https://www.mid-atlanticshow.com/
Other than that, I usually just go to the Chantilly show when I remember that it's actually happening.