Objectives: To perform computational studies on different combinations of plate fin arrays of different shapes for studying their performance in natural convection heat transfer. To compare the heat transfer performance of uniform notched fins with hybrid notched fins and also performance of normal notched fins with inverted notched fins. Methods: SolidWorks Flow Simulation software is used for the present computational studies. Three types of vertical plate fin arrays viz. plain rectangular fin, rectangular fin with square notch and rectangular fin with semi-circular notch are used with their seven combinations. These fin array combinations are: plain rectangular, rectangular square notched, rectangular semi-circular notched, rectangular inverted square notched, rectangular inverted semi-circular notched, hybrid rectangular square-semi-circular notched and hybrid rectangular inverted square-semi-circular notched. Findings: The highest average heat transfer coefficient of 7.82 W/m2K is found to be for inverted hybrid square-semicircular notched fin array. This value of heat transfer coefficient is about 8% higher than compared to that with plain rectangular plate fin array (7.25 W/m2K) subjected to same operating conditions. Average heat transfer coefficients for inverted plate fin array combinations are high as compared with the non-inverted combinations. Also, hybrid plate fin arrays, whether inverted or not, show higher heat transfer coefficient values as compared with uniform notched fin arrays. Novelty : Seven types of plate fin array combinations are studied computationally. SolidWorks Flow Simulation software is used very effectively for this 3D CFD analysis. The behaviour of fluid i.e. air during natural convection flow is studied using air flow velocity trajectories. Surface contours are effectively used for studying variation in surface temperature and heat transfer coefficient at all locations of fin arrays. Keywords Natural convection, plate fin array, heat transfer coefficient, CFD, heat transfer enhancement