The older I get the more I realize that modders will never be satisfied until they've combined every game with every other game. One modder in particular, Kaze Emanuar, is spending his time building Super Mario Odyssey into Mario 64 (opens in new tab) but with all the fancy features you'd expect like Mario's new hat moves, the ability to possess different enemies by tossing your hat onto them, and even the levels themselves. It's an enormously impressive bit of work, and you can see Emanuar's progress in his latest video above.
I actually just finished Odyssey a few months ago and I'm amazed at how similar Emanuar's version is despite sporting the clunky graphics of Mario 64. All of Mario's abilities appear to be in working order even though there's no animations for him actually throwing his hat or possessing various creatures found throughout the level (yet).
But I'm sure with more time, Mario Odyssey 64 will get there. Once finished, Mario Odyssey 64 will have between 240 and 300 moons to collect across all of Odyssey's different levels.
Emanuar is no slouch when it comes to modding Mario 64 to do incredible things. He also made a different Mario 64 romhack (opens in new tab) called Last Impact which effectively turns it into an entirely different game, complete with additions like the F.L.U.D.D. water cannon from Mario Sunshine and more.