In this review paper, the state-of-the-art vehicle-to-everything (V2X) mode operation of electric vehicles (EVs) is discussed. All the other modes of operation which are enabled by the V2X functionality of the system like Vehicle-to-Grid (V2G), Vehicle-for-Grid (V4G), Vehicle-to-Vehicle (V2V), Vehicle-to-Home (V2H), and Vehicle-to-Load (V2L) are discussed in detail. The V2X functionality is used to provide various services to the system like regulation of active power demand, reactive power compensation, shaving peaks and filling valleys in load demand, frequency and voltage regulation, compensation of harmonics in grid current. The techniques which are used to control the EV in V2X mode to impart the above-mentioned services are included. The advantages and limitations of these techniques are also discussed in this paper. The interaction among different modes of operation of EVs like V2G, V4G, V2V, V2H, and V2L is studied. Battery degradation, cyber-attacks, time-delays encountered in communication channels, and stability issues are the major challenges that may pose the threat to the resiliency of the V2X system. These dominant challenges are included in this paper. The methods which are used to enhance the resiliency of the V2X system against these issues are discussed as the scope of future work.