The phrase "was crawling with" refers to an abundance or overabundance of something, typically in reference to living creatures. Synonyms for this phrase could include "teeming with," "swarming with," "infested with," "overrun with," "abounding with," or "inundated with." Each of these synonyms highlights the idea that the quantity of the creatures in question is high or overwhelming. Additionally, these synonyms can also be used to describe non-living things, such as an area that is "flooded with" or "crowded with" objects or people. As a writer, using different synonyms can help to add variety and interest to your language, making your description more engaging for readers.