The next obvious one that comes to mind is Die Große Fuge. This video has a bunch of examples of fugues in Beethoven Symphonies, though IMO none of them are among the strongest like Die Große Fuge is. That said, this guy disagrees with me and claims the fugue in Beethoven's 9th Symphony's final movement is the best Beethoven. He also says that of the Romantic and post-Romantic eras, Mahler's 8th Symphony, 1st movement, is his favourite. I'd have gone with the Bruckner he references, which is probably from the finale of the 5th Symphony, but I'm not the biggest Mahler fan in general.