<p>Mixing fluids in microfluidic and miniaturized devices such as micromixers poses a formidable challenge due to factors such as laminar flow, limited fluid diffusion for mixing, and low Reynolds numbers. The use of active micromixers with stir bars can promote a more homogeneous mixing process. The current investigation focuses on evaluating the mixing behavior of both Newtonian and non-Newtonian fluids in various micromixer configurations. Non-Newtonian fluids are described by viscosity models, including power-law, Bingham-plastic, and Herschel-Bulkley models. The micromixers are designed in different geometric shapes, including circular and elliptical chambers, featuring single or paired blades. A meshless particle-based method known as smoothed-particle hydrodynamics (SPH) is used to numerically solve the governing equations. SPH operates in a Lagrangian framework and is therefore particularly suitable for modeling flows with moving boundaries, such as rotating and oscillating blades, and for complex geometries. The accuracy of the computational code is verified by comparing the results with previous experimental and numerical studies. The findings reveal that the two-blade circular mixer exhibits superior efficiency in mixing non-Newtonian models, whereas the one-blade circular mixer is more effective for mixing Newtonian fluids. Furthermore, the elliptical micromixers outperform their circular counterparts, especially during the initial cycles of blade oscillation. These results highlight the importance of considering local performance when selecting the type of micromixers, especially when specific mixing constraints or a certain level of homogeneity at a specific time are required for the mixing process.</p>