Quoted By:
Cosmic type is the only logical and useful type that could be made. There are Pokémon who canonically came from space, there are moves that fit this type and it isn't as gay as light or sound.
Pokémon that would certainly become Cosmic type:
>Cleffa line, Fairy/Cosmic
>Ledyba line, Bug/Cosmic
>Volbeat/Illumise, Bug/Cosmic
>Lunatone/Solrock, Rock/Cosmic
>Chimecho line, Psychic/Cosmic
>Deoxys, pure Cosmic
>Lumineon, Water/Cosmic
>Cresselia and Darkrai, Psychic/Cosmic and Dark/Cosmic
>Gothita line, Psychic/Cosmic
>Elgyem line, pure Cosmic
Also others, but these are the most obvious.
There's also a shitload of Pokémon you can design to be Cosmic, based on things such as meteorites, UFO's, aliens and other stuff.
Pic related is a possible type chart for it, makes sense to me
