The mystery has led to plenty of fan theories, with one from Pokemon YouTuber Light proposing that an easily missed line from ...
Z-A seems to serve as the 'Z' to Pokemon X and Y over ten years later, and if that's the case, then two more ideas should follow.
Fire Red & Leaf Green provide various ways to replay with diverse Pokemon and strategies. Titles like Ultra Sun & Moon, Let's Go Eevee/Pikachu, Legends: Arceus offer intricate stories, fun minigames, ...