I've been trying to find some sources on various international W.i.t.c.h. releases but have struggled to find most - for obvious reasons Italy's easy to find but many countries have very little consolidated information on their releases - so I have made some pages for the countries where I have some of the comics. You should be able to see the links to the left.
That said, Egmont Bulgaria does still have its W.i.t.c.h comics and books listed on its website.
Here are some links to other fans' pages where they do something similar for their country's releases:
Here are some links to some more general sites which document comics:
And, of course, various countries on I.N.D.U.C.K.S.:
Note that some of these titles are aproximate machine translations.