All media types
swisscovery RZS ZHB/Uni/PH (discovery tool, first-level search)

Books only (print)
swisscovery RZS ZHB/Uni/PH (confine to: 'format': 'books': 'in libraries')
swisscovery Switzerland (confine to: 'format': 'books': 'in libraries')

Databases only
DBIS (Database info system) Political Science (discipline-specific databases and interdisciplinary resources relevant to the discipline)

Online journals only
BrowZine Political Science (wide selection of e-journals from all subfields of the discipline; full text from 2005 onward)

E-books only
ZHB e-books (variety of e-book packages, some with political content)

Reference works only
Oxford Bibliographies Online: Political Science (annotated literature lists compiled by renowned specialists on a wide range of topics in political science)
Oxford Bibliographies Online: International Relations (as above but for international relations)
Oxford Research Encyclopedia Politics (encyclopedia delineating current research topics in all subfields, continuously updated and expanded)
Oxford Research Encyclopedia International Studies (as above but for international studies, with rich international relations content)
SAGE Handbook of Political Science (published in 2020; two-volume reference work from 2020 with good content on theories and methodologies; ed. Dirk Berg-Schlosser et al.)
Encyclopedia of Political Science (comprehensive reference work on the discipline from 2011; ed. George T. Kurian)
International Encyclopedia of Political Science (published in 2011; top-level encyclopedia from 2011; ed. Bertrand Badie et al.)
International Encyclopedia of the Social and Behavioral Sciences (IESBS), 2nd. ed. (authoritative 28-volume lexicon from 2014 with rich political science content)
Oxford Reference Online: Politics (licensed and unlicensed reference works on politics and international relations from Oxford University Press)

Journal articles only (online)
E-newspapers (national and international press portals)
EUObserver (independent online newspaper reporting from the EU headquarters in Brussels. Focal points: human rights, transparency, anti-corruption, environmental protection and democratization in EU countries)

Gray literature/research reports only
BASE (Bielefeld Academic Search Engine) (search engine for open access documents from institution servers worldwide, theses, unpublished research reports, preprints, etc.)
Columbia International Affairs Online (CIAO) (international relations database published by Columbia University. Primarily recommended as a source for U.S. foreign affairs, with unpublished reports and papers from foreign policy think tanks)
IREON-Portal (gateway for practitioners of international relations and area studies, providing free access to searches in relevant databases including LITDOK, the database of the German Gesellschaft für Internationale Zusammenarbeit (GIZ). Good content in terms of working papers and other types of gray literature).