Due to their intriguing electronic properties and structural composition, transition metal oxides (TMOs) such as AOx, AxOx, and AxB3-xOx; A, B = Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Mo, W, etc., and their designed composites have tremendous potential in energy storage devices such as supercapacitors (SCs) and metal ion batteries (MIBs). Some outstanding properties of TMOs and their composites for applications as electrode materials in energy storage devices include their high conductivity, charge storage characteristics, doping potential, and composite forming propensity. The significant interactions of TMOs with heteroatoms, conductive polymers, and carbon nanomaterials (CNMs) drastically change the reactive parameters and electrical characteristics. This review covers the most recent advances in TMO research and development, ranging from mechanism design to device performance, with a main focus on essentials such as design, synthesis, manufacturing, and energy-storing properties. The electrochemical pyrolysis, in-situ preparation, solvothermal/hydrothermal approach, and other critical approaches and their implications are also discussed. The synergetic improvement of designed TMO/graphene, TMO/rGO, TMO/heteroatoms, TMO/polymers, TMO/halide/hydride, TMO/Chalcogens through ionic interactions, and investigation of the electrode–electrolyte interfaces have been discussed in detail. In addition, the effect of electrolytes, surface behavior, and performance evaluation parameters on the SC device performance have been included. Furthermore, parameters and models, reliability design and profile lifetime, common mistakes in performance evaluation of SC, and other obstacles and mitigation have been described in depth. Altogether, a well-grasped overview and potential strategies extended from the overall analysis of electrode materials and electrolytes are offered to lift advancement in developing futuristic materials for energy storage applications.