The relative incompetency of rectangular galloping excavators against conventional circular VIV harvesters is already known. In this experimental study, the hydroelastic energy performances of new right-angle isosceles triangular cylinder against circular, square and diamond cross-sections are investigated. The triangular cylinder displays VIV or galloping type of response in four different symmetrical and unsymmetrical configurations tested. The results show the distinct higher overall galloping energy performance of the triangular cylinder in Config. 2 among other VIV and galloping harvesters. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is employed to order the remaining tested cross-sections using the averaged and maximum values of the mechanical power and efficiency as criteria. The TOPSIS algorithm shows that the VIV diamond and circular harvesters stay at the second and third places of the energy performance, respectively. The preference value of the diamond and circular cross-sections are almost comparable but are less than half of that in Config. 2. In general, the sharp-edge cylinders display superior energy performance over circular cross-section. However, the axisymmetric circular cylinders, because of their omnidirectional performances, are more efficient in places with the varying flow direction.