COVID-19 pandemic has taken the world by surprise in the beginning of 2020. Initially detected in Wuhan, China, the newly discovered coronavirus has spread all over the world in a short time, which pushed the World Health Organization to declare the disease as a Public Health Emergency. The virus spread transmission primarily occurs between individuals when a contaminated person is in close contact with another person. Thus, contact tracing, the process of identifying and managing potential contacts that have been in a close contact with an infected person is a critical process toward limiting the transmission of the disease. Healthcare professionals with the help of researchers from academia investigated different techniques to deal with contact tracing. In this survey, we focus solely on Blockchain-based techniques that have been proposed so far to deal with contact tracing. We also survey existing Blockchain based applications and the privacy issues they may led to. We compare and evaluate contact-tracing applications based on a number of criteria, notably privacy, security, scalability, proximity estimation, possible attacks, latency, throughput, and resource utilization. We also present techniques that integrated Blockchain with Artificial Intelligence and we conclude this study by shedding light on the remaining limitations, challenges and future directions.