-Godzilla X or "Godzilla: The Legend Continues", an episodic sequel story to the Heisei series following Junior in a post-apocalyptic wasteland where him and the last remains of humanity team up to reclaim Earth against a new wave of monsters featured in the "Godzilla: Battle Legends" video game (Jyaramu, Shiigan, Vagnosaurus, etc). I kind of view this under the lens of "What if there was a late 90s anime Godzilla series".
-"Ultraman vs Flying Robot: Ultimate Giant Deathmatch", more of a simpler monster mash formatted as a 60s film script idea in which Ultraman and Giant Robo (of "Johnny Sokko and his Flying Robot" fame) team up against the Zettonian aliens, taking place after the events of both series. My dad was a fan of both series as a kid, so this would be kind of a fun thing for him too.
-Untitled Gamera Story, one that applies a sort of "meta-fiction" lens to Gamera similar to Super Monster in which the Gamera franchise was inspired by an actual heroic flying turtle of the same name who became lifelong friends with an orphaned boy. They grow up, grow old, and eventually part ways, until one day the Earth is put under peril. Together, they go on one last adventure against an alien threat. I remember the idea being inspired by some twitter post I saw months ago, I'll have to track it down and give big credit to OP
