There are many synonyms that can be used in place of "large number." Some examples include numerous, copious, abundant, myriad, plentiful, substantial, extensive, ample, and countless. Each of these words imply a great amount or quantity without specifying an exact number. "Numerous" and "copious" suggest a significant amount, while "abundant" and "myriad" convey an almost overwhelming quantity. "Plentiful" and "substantial" indicate a more than sufficient amount, while "extensive" and "ample" imply a vast quantity. "Countless" simply means too many to be counted. By using these synonyms, writers can avoid using repetitive language and provide a more varied and engaging reading experience.