What is uncited references? I came across this article which has section named uncited references. 

Why it is there and what is the purpose of that section ?
Note that the article you linked to is a review article. A review article summarizes primary literature, often reporting on the most important findings regarding a particular question or questions being addressed. In reviewing many articles, there may be papers that the author(s) reviewed in order to derive the results and major findings of the paper, but that didn't have anything interesting or exemplary of the major findings to report/cite directly in the manuscript. In that case, the author(s) would still need to cite the paper somewhere because it was part of the data collection component of the manuscript.
Journals may deal with those references in different ways. When feasible, authors may have few enough references such that they fit into a table in the manuscript, or they may report papers used in the data collection as supplementary data. If neither of those options is used, the author must cite those papers somewhere in the manuscript because they were a part of the study, and an &quot;Uncited References&quot; section may be one option for doing that.