One of the most exciting moments in the history of Hall H was when Legendary Pictures first made clear their intentions for a Godzilla movie, exhilarating fans in a way that didn't subside until it hit theaters. Now during their panel here at Comic-Con, not only did they confirm Gareth Edwards returning to write and direct, but they even teased which monsters Godzilla may face.
A brief video was shown featuring Edwards as he was filming a "small little sci-fi movie" from a "galaxy far far away", confirming he'll direct Godzilla 2 when he's finished. That would be finished with his Star Wars spinoff, and perhaps the biggest news to come out of this is that he feels comfortable enough to reference it as a joke.
After that was done, Legendary Pictures' Thomas Tull said he wanted to show us the monsters they were thinking about as Godzilla opponents. He then showed a teaser featuring Rhodan, Mothra, and Ghidorah, closing with the words "LET THEM FIGHT!"
Godzilla 2 is a very long ways off, which is why it may be smart to take this with a grain of salt. These are just what Edwards and Legendary HOPE to be in the film, but obviously the script could change everything.