All three of those types blow, especially Wood and Wind.
Wood is entirely covered by Grass. Grass really should've been named Plant. I think it was originally, but I'm not sure.
It'd be nothing more than a physical-based version of Grass.
Wind is entirely covered by Flying, especially since attacks such as Gust and Aeroblast are all Flying type.
And Wind would just be a Special-type version of Flying if it did exist.
Of those three, Holy is the most likely of them. Before you say, "N0 iT w00d b3 t3h LITE type inzt3d cUz 0f DARK!!!1!1!1!11", you should know that in the Japanese version, Dark was called Evil ("Aku" to be exact, but if I remember right that translates to Evil).
And what's the opposite of Evil? Well, Good. But a "Good-type" would sound even lamer than Wind and Wood, so the closest thing would be Holy. Though, it probably would end up as Light in the American version...
As for a type that might actually be likely to exist--try Sound. Levitate isn't the only "blocks a certain type of attacks" ability--there's Soundproof, and also Cacophony (the unused ability, which does the same thing). If Sound was made into an actual type, these would probably shift to blocking Sound-type attacks, rather than "sound-based" ones.