You have two fairly paths: zoom lenses or prime lenses. The IQ of prime lenses are great, but the flexibility of zoom lens is nice.
Since you already have a 50m prime lens, a 28mm or 35mm prime lens may be a nice addition (I would prefer myself the 35mm) and give you a wider angle. You could complement it with a 90 or 100mm prime lens.
For a zoom lens, both the 75-150mm and 80-200mm would not cover the wide angle. You could consider a 18-200mm instead.
Check also the Users' reviews in this Forum for these lenses.
Hope that the suggestion will assist...