The most stylish monograms I have seen are indeed Scandinavian; I include with them the monograms of the Romanian royal family, which all take the form of a cross using the initial at north, south, east and west. I am sorry I do not have pictures to illustrate them.
Interestingly (for me) while clearing out a lumber room I cam across old magazines from the Victorian era; I saw in the personal classifieds of one 1860s publication several invitations to "exchange" monograms. Apparently they were printed and bought as one would collect picture post cards. One doesn't have to be royal or noble to have a monogram, though I assume it would be frowned upon if a commoner or non-armiger capped it with a coronet.