With more types, it could be extremely easy to create a team with all types and make battling easier than it already is, so more types will help the game, battle-wise. These are some types I'd like:
Light: Pokemon really missed out on this one with Ultra-Necrozma
Dark: Not the same as dark type in pokemon as that mainly covers evil and even in japan, it's the 'evil' type, plus with having more than 2 types, singling elements are more needed.
Emotion: Nexomon that consistently show extreme emotion.
Hero: Nexomon that are extremely strong and not prideful.
Sound type: Too much noises could be used as a weapon, an annoying weapon.
Drake (Dragon): Not a copy, we have greater and lesser drakes, enough to make a type I hope.
Ice: Seperate it from water pls.
Spectral: Psychic and ghost are mixed into arcane, although a ghost could be considered arcane, where's the fun in that?
Sturdy: You don't have to be a rock or any associated material to be sturdy.