Hello! Think the Bufo gattatus, commonly known as Smooth Sided Toad, is a doable thing. They are widely available and only need to check for their availability at places you visit (i.e. Zealand or the U.S.). No idea about the former; but in the U.S., would advice looking into the amphibian section at Kingsnake classifieds. There are seller reviews at the forums testimonial section or you can ask here about any vendor before ordering your toads. Some of them do deliver to Europe but imagine that is very expensive unless doing large orders.

In regards to Bufo japanicus, that is a different story. Have not seen them available here, so your best chances is to find a source in Japan that could ship to you. Good luck !