The constitutional monarchies respect each others' land ownership and colonies, but in terms of actual power the British Crown dwarfs everything, especially if one correctly recognizes the USA as their vassal state.

Outside of this there are few strongmen-led states of non-royal blood, of which China is the most important one.

And then there is Switzerland, which is part of the democratically-pacified buffer zone around Liechtenstein ;)

Let's hope the people at the top don't become too crazy.