Logos Bible Software are offering the following free resources. Can’t vouch for all of these but definitely worth getting 17 free Sproul books in the “Crucial Questions” series.

Faithlife Study Bible
A free study Bible with layers of notes, infographics, videos, maps, etc. Originally Logos were going to sell this product for about $90, but the CEO decided it was something he wanted to offer for free. If this were available in print it would be 12 feet thick!

Logos App
Over 60 free books.

Noet App
10 free books for downloading the app, an additional 18 free books are available for creating an account or logging in to an existing account.

Free Book of the Month
One free book each month.

R. C. Sproul Crucial Questions Series
17 free books.