Blockchain technology continues to develop and its use in the industry is growing at a very high pace. A huge number of different blockchain technologies are available, each one presenting different characteristics, and different possible configurations. The huge amount of combinations may be very difficult to evaluate and compare, both directly and in terms of consequences on the target project. In this context, we propose an agile, yet effective taxonomy for blockchain technologies, allowing to easily highlight the aspects relevant to a target project. Furthermore, we overview the most relevant blockchain technologies at the time of writing and present practical guidelines to select a blockchain technology. Finally, we apply the proposed methodology to two real case projects, showcasing its functioning.