Originally posted by CBM lens pairings with the K70/KP would be appreciated...but maybe that's a separate thread.
There are a few threads on this, Chris, which might be worth reading before starting another. But if you want to pose the question and get informed answers (rather than just a reflection of people's own likes), you need to describe what you have, what you like and dislike about those lenses, what your photographic preferences are, and what you are looking to achieve with a new lens.
I gather from your posts and profile that you have a DA 18-135, DA 20-40 Ltd, DA 55-300 PLM and DA 50 f1.8. That's an extremely versatile and capable kit that covers a wide focal range. If you were going to add to it, it would probably be a specialty lens, such as an ultra wide angle lens or a long telephoto lens or a macro or an astro lens or a fisheye, depending on your preferences. But unless you already have a particular craving for one of these, since you haven't had this kit very long I'd suggest spending some time really getting to know what you have. That will give you a better idea of how you would like to shape your kit in future. Many people find the challenges such as "Single in ...[month]" a good discipline in doing this.
The other thing is software. If you are still getting to know Lightroom, there's a long but rewarding learning curve there.