Spatial, proper-motion, and parallax distributions of stars in the fields of NGC 2192, NGC 2266, and NGC 2509, illustrating the membership selection procedure based on Gaia DR3 astrometry. In each row, the left panel shows the spatial distribution of all sources within the adopted cluster radius (gray points), with probable cluster members highlighted in red. The middle panel shows the corresponding proper-motion distribution, which demonstrates the tight kinematic clustering of member stars. The right panel shows the parallax histogram, where the red distribution indicates the selected cluster members and the gray distribution represents the full sample. These plots demonstrate the effectiveness of the membership analysis using a Gaussian mixture model applied uniformly to all clusters studied in this work.