5G NR utilizes and further enhances OFDM- based techniques to deliver a much higher degree of flexibility and scalability while maintaining system complexity. One promising approach to developing advanced 5G waveforms is to combine OFDM with other technologies. Enhanced OFDM- based schemes are expected to adapt application scenarios such as massive Machine Type of Communication with low power consumption and Ultra-reliable and low-latency communication while utilizing and enhancing the mobile broadband service. This paper will review the OFDM technology variants that have evolved in the 5G era. Three typically enhanced OFDM-based techniques, including Flexible configured OFDM (FC-OFDM), Generalized DFT-s-OFDM (G-DFT-s-OFDM) and OFDM with Index Modulation (OFDM-IM) are discussed in the paper. The paper examines the performance of the three through the design process, potential service scenarios, hardware compatibility, implementation complexity, and main advantages in 5G era. The potential of OFDM-based methods is demonstrated from various angles. The performance analysis shows that well- designed OFDM-based techniques have excellent spectrum efficiency, flexibility, and infrastructure compatibility over multiple application scenarios. One should consider OFDM- based waveform as one promising candidate for 5G & beyond wireless communication.