The municipal archive of Rotterdam (Stadsarchief Rotterdam) has recently made a number of databases available under CC0, which might be of interest to the Wikidata community. These include birth, death and marriage data for the period 1811-early to mid 20th century, as well as cadastral data for 1832 and a street name database. They can be accessed here
http://www.stadsarchief.rotterdam.nl/vraagbaak/open-data (in Dutch only). If anyone decides to reuse these data, please share it here as well so that the archive can also be informed on any use.