For a more opinionated take on a lot of this, see the (circa 1999) Chicago undergraduate mathematics bibliography (<a href="https://www.ocf.berkeley.edu/~abhishek/chicmath.htm" rel="nofollow">https://www.ocf.berkeley.edu/~abhishek/chicmath.htm</a>) which now has a GitHub page and is being occasionally updated again (<a href="https://github.com/ystael/chicago-ug-math-bib" rel="nofollow">https://github.com/ystael/chicago-ug-math-bib</a>)