The Mikolaiv regional archive's digitized documents include metric books and state registration records from the 19th century through 1940s, house books listing extensive information in Mikolaiv's individuals and communities in the 1930s-40s, and audit records of Mikolaiv's Jewish population 1806-1875.
A multimedia project on Babyn Yar and the history of the Holocaust, WWII, and the Soviet period in Ukraine by the Holocaust Memorial Center of Babyn Yar in Kyiv. The entire website is worth exploring, but two main areas will be of use to researchers. For a large digital library collection featuring many different kinds of sources, go to "library" (бібліотека) and then "explore library" (дослідити…