You can find wallpaper in paint shops, or at least the people there can point you to a shop. You should probably aim to visit a physical shop to see the paper a

You can find wallpaper in paint shops, or at least the people there can point you to a shop. You should probably aim to visit a physical shop to see the paper at scale and feel it (there are more aspects to wallpaper than merely an image on paper). They will also have style books you can browse for inspiration. Also, don't necessarily think about wallpaper as something merely covering the walls - think of it as a decoration, in the same vein you might hang art. As you mention, it doesn't have a structural purpose. One way I've seen used to great effect is to paper only a single wall in a room, with a very bold wallpaper - eg behind the dining table in a large/long kitchen. It helps to "break up" the room in two sections.