The rapid development of information and communication technology (ICT) at the beginning of the 21st century caused a radical increase of publicly available databases and data sets related to security. A vast number of open-source Internet-based statistical data, indicators, indices, reports and information graphics is now covering almost every aspect of contemporary security issues. The creators of these databases are relevant national and international institutions, universities and think-tanks, private companies, non-governmental organizations, and individuals. The main goal of this paper is an overview of the existing databases through classification given by various authors, which will have epistemological and practical value for academic researchers, both from universities and research institutes, as well as for security practitioners seeking the state-of-the-art in security business.