PLOS (Public Library of Science) is a nonprofit publisher and advocacy organization founded to accelerate progress in science and medicine by leading a transformation in research communication. PLOS entered the publishing arena in October 2003 with the launch of PLOS Biology, followed in October 2004 by PLOS Medicine. Today, it publishes a suite of influential Open Access journals across all areas of science and medicine. The Max Planck Society covers article-processing charges for Max Planck authors centrally. Further details are available on the MPDL website.

Various dictionaries are available.

Project Gutenberg is a volunteer effort to digitize and archive cultural works. Founded in 1971 by Michael Hart, it is the oldest digital library. Project Gutenberg's mission is "To encourage the creation and distribution of eBooks".

A digital archive of life sciences journal literature managed by the National Center for Biotechnology Information (NCBI) at the U.S. National Library of Medicine (NLM).

Refubium is a service of the university library of the Freie Universität Berlin. As an institutional repository it collects documents, dissertations, postdoctoral theses, and research data.

MPG Resource Navigator is a web application to navigate through scientific information resources available to staff and guests of the Max Planck Society. It includes licensed databases, digital collections, and reference works. In addition, recommendable retrieval tools available on the web free of charge are part of the collection. Moreover, almost all Max Planck Institute library catalogs, as well as selected external ones, are accessible from here.

Springer Nature publishes the largest available collection of reproducible laboratory protocols and methods for the life sciences. The Experiments platform provides accees to the content from SpringerProtocols, Nature Methods, Nature Protocols and Protocol Exchange through a single easy-to-use platform, designed to save researchers' time.

The BSZ develops and maintains the SWB database in cooperation with 1,200 libraries in Baden-Württemberg, Pfalz, Saarland and Sachsen. The online catalog offers bibliographic data free of charge: Monographs, periodicals, articles, loose-leaf collections, off-prints, conference proceedings, university publications, reviews, abstracts, tables of contents, maps, music, audiovisual material, microforms, electronic resources (data media), online resources; scientific and popular literature from all subjects and in all languages from the 15th century to the present; scientific literature (according to the DFG special subject fields programme) from theology, ancient orient, art, music, archeology, law and criminology;

EVIFA, the portal of Social and Cultural Anthropology, offers anthropological and folkloristic information from one source. It gives a fast, comprehensive access to specific information for anthropological research, regardless of the where about.

The World Bank is the largest single source of development knowledge. The World Bank Open Knowledge Repository (OKR) is The World Bank’s official open access repository for its research outputs and knowledge products. Through the OKR, the World Bank collects, disseminates, and permanently preserves its intellectual output in digital form. The OKR also increases the range of people who can discover and access Bank content - from governments and civil society organizations (CSOs), to students and the general public. The OKR is built on DSpace and is interoperable with other repositories. It supports optimal discoverability and reusability of the content by complying with Dublin Core Metadata Initiative (DCMI) standards. All OKR metadata is exposed through the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) protocol. By extending and improving access to World Bank research, the World Bank aims to encourage innovation and allow anyone in the world to use Bank knowledge to help improve the lives of those living in poverty.

You can search for popular books, music CDs and videos—all of the physical items you're used to getting from libraries. You can also discover many new kinds of digital content, such as downloadable audiobooks. You may also find article citations with links to their full text; authoritative research materials, such as documents and photos of local or historic significance; and digital versions of rare items that aren't available to the public.

zbMATH Open (formerly known as Zentralblatt MATH) is the world's most complete and longest running abstracting and reviewing service in pure and applied mathematics. The MATH Database contains several million entries drawn from more than 3,500 serials and journals, and more than 1,100 book series and monographs. The entries are classified according to the Mathematics Subject Classification Scheme (MSC 2000).

The ZDB is the world’s largest specialized database for serial titles (journals, annuals, newspapers etc., incl. e-journals). The ZDB contains more than 1 million bibliographic records of serials from the 16th century onwards, from all countries, in all languages, held in 4000 German (and some foreign) libraries, with holdings information. It does not index individual journal articles.

Zenodo is an open data repository, developed and operated by CERN. It is an catch-all repository, that welcomes research from all over the world, and from every discipline. Zenodo does not impose any requirements on format, size, access restrictions or licence. A digital object identifier (DOI) is automatically assigned to all Zenodo files and it is integrated into reporting for research funded by the European Commission.