Proto-Indoeuropean language (p-IE) has been the subject of study for more than 200 years, and a great deal of work has been published has been written about p-IE reconstruction. In addition, there are ancient languages that have allowed the reconstruction of many details that in modern languages have been lost or are obscure.
But outside, the Indoeuropean language family, which other deep-level proto-languages have been reconsctructed with more details? I recently read that the last two reconstructions of Proto-Afro-Asiatic, for example, have very little resemblance and the number of common reconstructed lexical items is small and there are large differences between the two proposed reconstructions.