Siansaar's Changeling ideals, Marine Biology, animals in general especially reptiles and marine life, Hunt Showdown (Best game for extreme stress lmao), Monster Hunter (Best game franchise around!), science especially biology and thas about it I think?
In my opinion, nothing will ever be cooler then boss crossovers... I mean come on Ridley, Bowser, M.Bison, Sephiroth, baddies like that working together is so satisfying...
On top of that, Ridley and K.Rool were announced too recently if I recall? Finally as proper parts of a Smash game... Only took Ridley two decades to be playable...