Some of my favorite endings in recent memory, such as Crown 2013 and Bluecoats 2014, made their debuts around the time of Atlanta. Therefore, I wouldn't be surprised if, by then, we have new endings from corps such as Crown, Cavaliers, and Crossmen.
Blue Devils have had a few days off, so we could see their new ending at Houston and/or SA.
Also, I think someone stated on another thread that Phantom usually has their new ending around the time of Allentown.