Heat transfer removal rate from surfaces is great importance in many engineering applications. For many industrial applications like automotive, air conditioning, electronic cooling, spacecraft and aircraft applications, internal heat generation can cause overheating problems that may result in system failure, short machine life, need of maintenance and low system reliability. To solve such problems passive cooling techniques are widely used. This article summarizes an extensive literature review of rectangular fin structures that is much-used heat transfer enhancement technique with a high efficiency rate and a low cost. Moreover, in this study not only solid rectangular fin structures are studied but also inclined, perforated and staggered type rectangular fin studies are summarized. To increase the heat transfer rates and Nusselt number distributions, designers should optimize the parameters such as fin number, fin shape, fin height, fin diameter and inter-fin distance ratio for all of the fin types. In the optimization process of those components, designers should have experience with the fin design procedure; without the necessary experience and knowledge, instead of increasing the heat transfer rates, fin surfaces can resist and block the incoming air flow which will affect heat transfer rate adversely. This review is a guideline for designers presenting how rectangular fin arrays are used to enhance heat transfer rates.