My list according to http://www.worldatlas.com/nations.htm (no time to consider the contest "the world's greatest traveler". ):

Argentina
Austria
Bolivia
Brasil
Bulgaria
Denmark
Canada
Chile
China
Czech Republic
Germany
Hungary
Italy
Japan
Liechtenstein
Luxembourg
France
Indonesia
Malaysia
Mexico
Monaco
Myanmar/Burma
Netherlands
Paraguay
Peru
Poland
Singapore
South Africa
Spain
Switzerland
Thailand
United Arab Emirates
United Kingdom
United States
Vatican City
Vietnam