I participated/created similar challenges in the past and thought they were kind of fun. The goal of this is to read a certain number of books published in each respective year. Reading the number of books in the ones place; for example, for 2015, you'd read 5 books published then. For 2020, the goal would be to read 10 of them (only because who wants to read 0 books for a specific year?)

Read anything you want! I try to kind of extra challenge myself and only include novels/novellas type things but manga/comics/whatever you read totally counts!