I love JLAvengers and even DC vs. Marvel from the 90s. Batman vs. Punisher is great. But I have to say Batman vs. The Incredible Hulk might very well be the best of them all (story wise). It’s definitely the most underrated IMO. John Byrnes Batman Capt America team ups are fantastic as well. Theres a bunch more out there what’re some of your favorites.
Also if/when the big 2 ever crossover again what would you like to see? Personally I’d die for an epic maxi-series going deep into both universes mythos’. I know it’ll never happen, but that doesn’t change the fact thats what I’d really love for them to do .