The phrase "in large quantities" indicates a sizeable amount of something. Some synonyms for this phrase include "in bulk," "in abundance," "in great numbers," and "in profusion." Other options may include "in droves," "in masses," "in heaps," and "in bundles." These synonyms can be used to describe anything that is available or present in significant amounts, from food and clothing to data and information. Whether you are writing an article, a report, or a speech, using different synonyms can add color, variety, and clarity to your writing.