What about a Trick Room-themed gym? Or a Perish Trap themed gym? Or a Volt-Turn gym (god, maybe not)? Assist Shuffle? Baton Pass? Anything involving entry hazards? I want variety!!
If you people want type specializations, perhaps the Elite 4 can each specialize in one of the weather effects, which is sort of monotype.
1 - Gravity
3 - Assist Shuffle (would be the singularly most frustrating gym in history lol)
5 - Perish Trap
6 - Trick Room
7 - Baton Pass