Efficient heat exchanger design is crucial for cost, sustainability, and energy conservation. Due to its importance, the research interest in optimal HX design has increased across various industries, especially in the aerospace sector. Here, compact heat exchangers with a heat transfer area compactness β > 400 are of high interest, mainly the plate-fin ones. These topologies are characterized by vertically stacked plates that separate the two fluids, and several ducts in which many different fin geometries can be employed. Selecting the right fin type and its geometric parameters to use in each fluid side is a fundamental and complicated step. Although optimal HX selection and design have been relying on the expertise and past choices of experts, over the years, several methods have been proposed to compare the performance of different surface geometries.