If you’re a zoom user then this is an easy question. Wide angle zoom to 24mm if that’s your thing, then a 24-70mm, 24-105mm, or 24-120mm. If you’re not into ultra wide, then drop the wide angle zoom and add a 70-200mm. If the middle ground is not your think then a ultra wide zoom like the 12-24mm f/2.8 and the 70-200mm f/2.8.
But what if you are into primes and want to travel small and light. Well its down to what you photograph and what focal lengths you enjoy.
When travelling with just my Leica, I take three lens, 24mm, 35mm and 50mm but you can argue that a 35mm and 50 are too close together. A 24mm or 28mm and a 50mm make sense but not the 35mm. If you had the 35mm your more into thinking about a 75mm, 80mm or 90mm. Many wedding photographers who do not use zooms often have a 35mm on one body and a 75mm / 85mm on the other.
I think it if was general use I would favour a 28mm and a 50mm. If I was shooting fashion with a model in the city streets then likely a 35mm and a 85mm, I might if shooting Nikon go as far as the stunning 135mm f/1.8 S Plena. Though I do know of one top New York fashion photographer who now uses a Leica Q with its 28mm lens for everything.