Hello Jacek. You might find these useful:
http://www.around-the-world.co.uk/public/regions.zip
Obviously I prepared them for my own specialist purposes, so they
maybe aren't accurate. From memory, my border between Europe and Asia
is not textbook. Also I include Australia in Asia. Many of my land
borders are quite detailed and therefore should be useful, but I have
to include quite a lot of sea in each continent. I have different
regions for the Atlantic, Indian Ocean, Antarctic and Pacific
(Oceania). Oh yes, my border between Asia and North America has to be
along the anti-meridian and I also had to split the Pacific into
Oceania East and West because I found that some MySQL GIS functions
don't (or didn't) handle the anti-meridian properly. I apologize to
any Russians who therefore feel twitchy about some of Eastern Siberia
being in the USA, but remember that you had Alaska for quite a long
time once :-) .
I hope that helps. If you develop anything better from these files,
please post a link here.