According to https://www.superduperinc.com/handouts/pdf/149_VocabularyDevelopment.pdf
The 6-year-old child typically has a 2,600 word expressive vocabulary (words he or she says), and a receptive vocabulary (words he or she understands) of 20,000–24,000 words.
I am looking for such 2,600 (or 20,000-24,000) word list. Any suggestions will be appreciated.
I think you've misunderstood what the passage is saying. Different children will know and use different words; the passage merely says that, for any given child of that age, the size of that child's expressive vocabulary will typically be 2,600 words.
Furthermore, while I don't know what research underlies its claim, I think it's unlikely to have involved obtaining a complete list of even a single child's expressive vocabulary; rather, it would more likely have used statistical techniques to estimate the number of distinct words that the child ever uses by examining the frequencies of words in some corpus of the child's speech.
