I am indecisive when it comes to wallpapers so I have a script somewhere which accepts tag-words as arguments and then scrapes wallhaven.cc for those words at the resolution of my setup and picks one that contains those words at random before downloading it to my wallpapers folder and setting it as my wallpaper image.
So for example, you could just know you want something blue so you would run wallpaper blue
and it just grabs one and sets it. You could get a wallpaper of the sky, of a blue car, of the ocean, whatever happens to be a wallpaper that met the criteria of the word/s supplied.