The proliferation of cloud-based applications, data, and services has significantly transformed digital interactions, driven by the widespread use of powerful smart devices and the expansion of cloud ecosystems. These ecosystems rely on data centers composed of Physical Machines (PMs) and Virtual Machines (VMs). The increasing demand for cloud services has led to extensive use of physical servers, resulting in high energy consumption and inefficient resource utilization. Consequently, optimizing resource allocation and reducing power consumption have become pivotal challenges in data center management. A key strategy to address these challenges is Virtual Machine Consolidation (VMC), which optimizes computing resources by consolidating multiple VMs into fewer PMs. This paper comprehensively reviews the three critical phases involved in VMC: PM detection, VM selection, and VM placement. Through an extensive analysis of literature spanning from 2015 to 2024, this review seeks to provide valuable insights into the current landscape of VMC and its potential ramifications on the performance and sustainability of cloud computing. The main flaw in the articles is that the various authors focused on different assessment metrics when the emphasis should have been on the three primary steps in VMC. The importance of this categorization lies in its ability to provide clarity, organization, and a structured framework for comprehending the intricate landscape of VMC. VMC is a multifaceted undertaking encompassing numerous subtasks. Categorization simplifies this complexity by breaking it down into manageable components. Researchers can address each category individually, potentially leading to more focused and effective solutions.