What are some unused or underused(only one Pokemon has it) type combinations you really want to see? And maybe what region archetype would you want it to be on?

I'm a big fan of bug and dragon types and it's a surprise it hasn't been combined yet. I think it'd be cool if they made it the pseudo-legendary, since when most people think of three stage bugs they just think the early route shitmon, but making a small weak bug type you find only mid to late game evolve into a super strong dragon would be fun. Maybe make it based on some kind of really large spider or wasp.