But I have personally found these books with extreme limited vocabulary to be much better read-aloud books for 2-year-olds than books for independent reading by 4–5 year-olds. More generally, many other graded readers are excellent read-aloud books. At age 2–3, my kids particularly enjoyed the Henry and Mudge books https://www.amazon.com/dp/1534427139, and everything by Arnold Lobel.
If you are trying to teach kids to read, let me highly recommend Bloomfield’s workbook Let’s Read from the early 60s, which I heard about from a 2012 comment here on HN by Tokenadult. https://www.amazon.com/dp/0814311156 https://news.ycombinator.com/item?id=4665466
Bloomfield was one of the leading linguists of his era, and his book is very carefully structured to introduce only one new spelling–sound association per lesson, with the first half consisting of only regularly spelled words, so there is no possible confusion, with the full mishmash of irregular words only introduced after the reader is already fluent with regular spellings.
My son & I started working through it together for about 10–15 minutes per day when he was 3.5 years old, and it took about 8 months to get to the end, after which he could fluently read pretty much any material he could comprehend. As a not-quite-5 year-old he now happily independently reads books intended for 3rd–4th graders. (I’m not trying to suggest every kid should start on such a project at that age; every kid is different, and interests and attention span vary.)
I like the stories in that book, too, especially the very last story.
Interpreting that as a request to name the textbooks I find useful, I'll do that here.
The Gelfand Correspondence Program series
Basic Mathematics by Serge Lang
The Art of Problem Solving expanded series
When a student has those materials well in hand, it is time to work on AMC and Olympiad style problem solving,
and also the best calculus textbooks, such as those by Spivak or Apostol.
By far the best initial reading text is
Let's Read: A Linguistic Approach
but there are many other good reading series, including
Teach Your Child to Read in Ten Minutes a Day
(I devote more time than that to reading instruction, typically, because I use multiple materials)
and quite a few others. There is more junk than good stuff among elementary reading materials, alas.