A lot of good advice.
(But "landscape" does not always mean "wide angle". I've shot landscapes with what ever lens focal length that gives me the angle of view that I want to show)
That said, my grouping of 6 focal lengths; 24-35-50-85-135-200, has been my standard for a long time and the three most common are grouped much like you would find on a rangefinder setup 35-50-85.
Because I value compact size and lighter weight the 24 is a f2.8, 35 f2.8, 50 f1.8, 135 f3.5, and the 200 is the tiny f5.
Someday.....perhaps....I might add the 300 f4.5. If I try hard enough I can convince myself it is a "need" and not a "want".
There is hardly any day that cannot be improved by at least one good rationalization.