This is the 100 most popular downloads on gutenberg.org.
I was inspired by the Reddit post by u/hackeryarn at: https://www.reddit.com/r/books/comments/doodup/chronologicallistofthetop100freeclassic/
…which in turn was inspired by u/Chtorr at: https://www.reddit.com/r/FreeEBOOKS/comments/9vy4oa/thetop100freeclassicebooksfromproject/
You can duplicate this list and use it to keep track of the books you read, and share the list with others.