The data-repositories and datasets described below contain both qualitative as well as quantitative data.
Empirical educational research:
VerbundFDB forschungsdaten-bildung.de:
https://www.forschungsdaten-bildung.de/
Catalogue of VerbundFDB of the datasets of educational research on their website:
https://www.forschungsdaten-bildung.de/studienliste.php
Overview of data centers in the field of educational research that provide additional data: https://www.forschungsdaten-bildung.de/fdz_bildungsforschung
The intructions are being constantly updated.
Datenbank zur Qualität von Schule
Leibniz-Institut für Bildungsforschung und Bildungsinformation
PISA
TalkBank
An overview of datasets available from the Institute of Education Sciences: Available IES Datasets.
From the same website, interesting can also be: NCES Data Tools (National Center for Education Statistics), and Resources for researchers.
Overview of video portals of educational research at the Forschungsdatenzentrums Bildung:
https://www.fdz-bildung.de/videoportale
Other research areas:
Open psychology data:
Harvard Dataverse
Johnson´s data repository on the Open Science Framework.
Open-Source Psychometrics Project.
Overview of social and economic data centers - also beyond educational research: https://www.ratswd.de/forschungsdaten/fdz
On this page there is also a meta-search possible in the holdings of the data centers involved: https://www.ratswd.de/forschungsdaten/suche
An international overview of data centers: re3data.org
Some more links to data-repositories or datasets:
CESSDA (Consortium of European Social Science Data Archives
DESTATIS
Eurostat
Fairsharing
Figshare
Harvard Dataverse
GESIS
IAB (Institut für Arbeitsmarkt- und Berufsforschung)
OECD
Open Science Collaboration