Plant genetic resources are fundamental materials for crop improvement to enhance productivity and an insurance against unforeseen threats to agricultural production. Continuous advancement in crop improvement depends on discovery of new sources of genetic variation, accurate identification of lines with favorable traits, and their efficient and judicious use. Core collections (~10% of the entire collection) and mini core collections (~10% of the core or ~1% of the entire collection) have been suggested as a gateway to enhance utilization of germplasm. Using passport data, characterization and evaluation data, core and/or mini core collections have been developed in chickpea, groundnut, pigeonpea, pearl millet, sorghum, finger millet and foxtail millet at ICRISAT, Patancheru, India. Evaluation of these subsets has resulted in identification of new sources of genotypic variation. The concept and process of developing mini core collections has been recognized worldwide as an “International Public Good” (IPG). Many national programs have shown immense interest in evaluating mini core collections for identification of new sources of variation for use in crop improvement programs. To date, 84 sets of mini core of chickpea, groundnut, pigeonpea, sorghum, pearl millet, foxtail millet and finger millet have been supplied to researchers in 13 countries. Feedback revealed that researchers in national programs were able to identify new sources of variation for favorable traits, such as early maturity, resistance to pests and diseases, large seed size, and high grain yield. Seeds of mini core collections could be available to researchers globally for research and training purpose.