Bug/Dragon
Electric/Psychic
Grass/Flying is the only concept that I'm really not a fan of. Bug/Dragon and Electric/Psychic were the two standouts for me; the only two that I think would fit this concept the best. There's a compelling argument for Bug/Psychic, but it ultimately came down to me thinking that the former two would do the best at creating risk for not only the user, but the opponent as well. Bug/Psychic just seems a bit too easy to wall for me to really create risk for the opponent. Bug/Dragon and Electric/Psychic both fit equally well in my opinion, but I do prefer Bug/Dragon because Dragon is my favorite type. Can't be completely 100% objective, no matter how hard I try. :P