My Board

Leipzig 1884-1937.
https://de.wikisource.org/wiki/Ausf%C3% ... Mythologie

ed. Dunnhaupt (3 vols.) can be borrowed at www.archive.org

has been published as database by the Staatsbibliothek zu Berlin under https://tw.staatsbibliothek-berlin.de/html/haebler.xql

can be borrowed from archive.org (https://archive.org/details/contemporar ... 3/mode/2up).

can be borrowed from archive.org (search for "Encyclopedia Renaissance").

Not a scholarly topic, strictly speaking. Free access for the next month:
https://www.digitalconcerthall.com/en/home

The project MUSE makes numerous books from Princeton UP, Cornell UP, U of Minnesota Press, Duke UP, Johns Hopkins UP and others freely accessible.
muse.jhu.edu

All the databases of MIRABILE. Archivio digitale della cultura medievale. Digital Archives for Medieval Culture are freely accessible until May 15, 2020.
URL: http://www.mirabileweb.it/

According to a mail I got this morning the Internet Archive ist suspending waiting lists, until June 30, 2020, or longer. This must mean that books in the lending section of the Archive can be used by multiple readers concurrently.
URL: www.archive.org

The scholarly ebooks of the University of Michigan Press are freely accessible online until the end of April 2020.
URL: https://blog.press.umich.edu/2020/03/um ... ee-access/