Because the navigation system on the Netherlands government ePub website has some room for improvement, to understate slightly, I have liberated 2835 of their ePubs and made them available as a single .tar.gz download [NOTE: 433 MB].
The texts are, of course, in Dutch. Most are laws, amendments, memos, AMVBs, etc. These texts are also available online on wetten.overheid.nl, with a fairly decent search interface.
Here’s a screenshot of calibre with the ePubs loaded:
