Learning your native language, how to count, read, write, maybe a little reasoning in there, like Euclid’s Elements. This level might as well be called Pre-Basic.
Issac Watts, Logic: https://archive.org/details/logicorrightuseo00watt
I've read most of this, but not sure if any of it stuck.
Euclid's Elements: https://www.gutenberg.org/ebooks/21076
And also colorful illustrations: https://www.c82.net/euclid/
I need to read this one eventually. Maybe when I retire and have absolutely nothing else better to do. I have spent more time than I should have lamenting that nobody bothered to put this book in front of me when I was a child.
Here's the Great Books of the World, well, the Western world at any rate. Produced / curated by Brittanica. I've read a few of the entries.