The phrase "pullulate with" is often used to describe a large number of something, such as crowds, animals or plants. If you are looking for alternatives to this phrase, you may consider some synonyms that convey the same meaning. For instance, you could use "abound with," "be teeming with," "swarm with," "overflow with," "brim with" or "be awash with" to signify a multitude of things. Other synonyms for "pullulate with" include "be densely populated with," "throng with," "be littered with," or "be crowded with." These terms are useful for writing descriptions or expressing large quantities in a more poetic or varied way.