One of the more effective methods for the generation of conformer ensembles is the Conformer-Rotamer Ensemble Sampling Tool (CREST). This tool uses RMSD-biased metadynamics to sample possible geometries for a system. The generated geometries are then iteratively screened and optimized to generate a final ensemble consisting of all conformers found in a given energy window (default: all conformers in the lowest 6 kcal/mol by energy).