8 part challenge, if you complete all 8, you'll get at least 100 books off your TBR. 

Note: Books you did not finish ABSOLUTELY COUNT for these challenges, since cleaning up your TBR is the whole point! However books cannot be counted for multiple parts of the challenge.

Part 2 - Prolific pens

Read 12 books on your TBR from authors who have written more than one book on your TBR.