For example, in Volume 4A there's a simple technique for comparing two pointers in bit-reversed form. This technique was patented by Hewlett-Packard as a method of randomizing search trees (treaps):
https://bugfix-66.com/fdb8bb4fa84cf810aa25ff40c88a13c1874410...
From Volume 3, here is by far the fastest method of sorting integers (Singleton's method), an algorithm I have used professionally several times (e.g., for beam search in a speech decoder):
https://bugfix-66.com/834f0677c85b23c0bf1047d3654ab7c27ff054...
Knuth's books are just packed with gems like that.
The meticulous high quality of the books is also remarkable. However, if you look very carefully you can find rare mistakes. I received payment from Knuth and have an account at his bank:
https://www-cs-faculty.stanford.edu/~knuth/boss.html
Getting your name on the above list was once a Hacker rite of passage.