<p>The flow direction algorithm (FDA) has garnereds significant attention from researchers and is increasingly being utilized across various fields to address diverse optimization challenges. This algorithm draws on principles of flow direction towards the outlet with the lowest elevation in a drainage basin, emphasizing the differentiation in objective functions and the spatial distance to neighboring points. This study provides an extensive examination of the original FDA, as well as its modifications and hybridizations. Additionally, the applications of the FDA in various engineering domains are explained. In general, FDA’s average ranking is relatively high. Lastly, the paper outlines potential avenues for future research in the advancement of the FDA.</p>