The ever-increasing demand for sophisticated cyber-physical systems (CPS) combined with the undertaking of the fab-less model opted by the design house, has led to vulnerability exploits in the IC supply chain, especially the insertion of hardware Trojans (HTs). The HTs are malicious modifications made to an authentic design to disrupt the functioning of the integrated circuits (ICs). In this work, we present a survey of the state-of-the-art HT designs focusing on the Trojan design, the risk level in the supply chain, and the targeted platform, followed by a discussion based on our observations. We categorize the HT designs based on targeted platforms like ML accelerators, IoT devices, FPGAs, ASICs, memory devices, CPU, and Cryptographic cores.