In this paper, we discuss about the notable locking-free techniques of several simple plate bending finite elements for the Reissner-Mindlin plate bending theory. The brief background for Reissner-Mindlin plate theory is presented, in which stress and strain derivation are given along with one-field and two-field variational approaches. Afterwards, we classify several efficient robust techniques in a cluster of main categories to present sequentially, which are all able to overcome the locking phenomenon in thick plate bending problems. Only selective algorithms are programmed to conduct numerical simulations. The corresponding results are compared between these elements to show their performances.