United States Patent & Trademark Office (USPTO) http://www.uspto.gov/

United States Copyright Office - http://www.copyright.gov/

World Intellectual Property Organization (WIPO) - http://www.wipo.int/portal/en/index.html

WIPO (oppositions) - http://trademark-oppositions.com/trademark-oppositions-wipo-international-trademarks/

WIPO Global Brand Database - http://www.wipo.int/reference/en/branddb/

European Union (OHIM) - https://oami.europa.eu/ohimportal/en/

European Patent Office Organization - http://www.european-patent-office.org/

International Trademark Association (INTA) - http://www.inta.org/

Argentina - http://www.inpi.gov.ar/

Australia - http://www.ipaustralia.gov.au/

Austria - http://www.austria.eu.net/patent/

Benelux - http://www.bmb-bbm.org/gb/pages/index.htm

Brasil - http://www.inpi.gov.br/

Canada - http://cipo.gc.ca/

Caribbean Netherlands, Bonaire, Sint Estatius, Saba - http://www.caribie.nl/nl

Croatia - http://www.dziv.hr/en/e-services/on-line-database-search/trademarks/

Denmark - http://www.dkpto.dk/

Estonia - http://www2.epa.ee/Patent/mark.nsf/SearchEst?OpenForm

Finland - http://www.prh.fi/

France - http://www.inpi.fr/

Germany - http://www.dpma.de/index.htm

Greece - http://www.obi.gr/mainen.htm

Hong Kong - http://info.gov.hk/ipd/eng/index.htm

Hungary - http://www.hpo.hu/

Iceland - http://www.els.is/merki/

Italy - http://www.european-patent-office.org/it/homepage/homepage.htm

Japan - http://www.jpo.go.jp/

Korea - http://www.kipo.go.kr/ehtml/eIndex.html

Macau - http://www.economia.gov.mo/en/web/public/navh

Malaysia  - https://iponline.myipo.gov.my/ipo/main/search.cfm

Malta - https://secure2.gov.mt/IPO/default.aspx?ct=2&date=19042015221627

Mexico - http://banapanet.impi.gob.mx/Contador/index.html

Norway - https://search.patentstyret.no/AdvancedSearch.aspx?Category=Mark&AspxAutoDetectCookieSupport=1

New Zealand - http://www.iponz.govt.nz/app/Extra/Default.aspx?sid=635651146393557208

Pakistan - http://ipo.gov.pk/Trademark/TrademarkJournal.aspx

Panama - http://www.digerpi.gob.pa/pls/digerpi2/web_busqueda.dato_marcas?age_wk=0&usu_wk=0

Peru - http://www.indecopi.gob.pe/

Portugal - http://servicosonline.inpi.pt/pesquisas/main/marcas.jsp?lang=PT

Romania - http://www.osim.ro/index3_files/database/datab.htm

Russia - http://www.rupto.ru/

Slovakia - http://registre.indprop.gov.sk/registre/searchForm.do?lang=en&register=oz

Slovenia - http://www2.uil-sipo.si/dse.htm

Spain - http://www.oepm.es/

Sweden - http://www.prv.se/

Switzerland - http://www.ige.ch/E/gisi.htm

Turkey - https://online.turkpatent.gov.tr/web/index.html

Taiwan - http://tmsearch.tipo.gov.tw/TIPO_DRE/BooleanIPORetriev

Ukraine - http://base.ukrpatent.org/searchBUL/search.php?action

United Kingdom - http://www.patent.gov.uk/