If you are into military history, Osprey Publishing is offering a selection of free eBooks every week. Each week they will be putting up a series of five books and you can select one or all for download.
This week the books range from a book on the Hawker Hurricane to Samurai of the mid 1500s. In between is the Battle of Waterloo, US Heavy Cruisers, and the Czech Legion.
The link is here. The code for this week is FREEBOOKS2.
Since you are stuck at home in most places by governmental order unless you are considered essential, you might as well put it to good use.