When it comes to expressing the idea that something is common, there are many synonyms you can use instead of "are prevalent." For instance, you could say that something is widespread, pervasive, rampant, or ubiquitous. These words all convey the sense that something is widely and commonly found, without necessarily being negative or positive in tone. Other synonyms for "are prevalent" include "are abundant," "are populous," and "are popular," all of which suggest that something is common and widely seen or experienced. By using these alternative expressions, you can add variety and precision to your writing, while still conveying the same essential meaning.