>>524355442/2
I think Light as a move property, like Sound or Contact or whatever, makes a lot more sense. Moves like Solar Beam, Moonlight and Sunny Day you could argue all "use light" in some way... it would be more interesting to give them all related properties, similar to how SV just defined what a "cutting" or "wind" move would be. Imagine if there were abilities that caused you to absorb Light attacks to power up SpAtt or if Chlorophyll and Solar Power were tweaked to activate if you were hit by a light move -- not just being activated by sun. There's a LOT more potential to get creative there, honestly.
My two suggestions aren't great, but they definitely don't "fit" anything we currently have in the game. A Digital type really would just retype the Porygons and then open up the door to some interesting new designs, similar to how Steel and Dark were gateways to really bringing in new ideas or evolutions -- only two old Pokemon actually got retyped, while everything else was pretty unique. Saint type could fit that bill as well, maybe.
And I'm just going to keep Reddit spacing because fuck you, I want to finish explaining myself. What I REALLY think they'll do for a new type is none of that shit I mentioned above. What I think we'll get is a retread of Shadow types from the GCN games, but it'll be something "new" like "Wild type" or "Chaos type." The idea would be that Pokemon will randomly be found with this new type that is a "super type," something that supercedes one of their types and gives them unique weaknesses and strengths -- similar to Shadow-type. It could even be something you add or remove from the mon, maybe like Teras, but there could also randomly be Pokemon that are "pure" of this type, like a "Wild" Eevee (Feraleon?) or maybe a legendary whose gimmick is that it keeps this typing and can't be purified.