"Counting heads" is a common phrase used to describe the act of taking attendance or tallying a group of people. However, there are several synonyms that can be used to replace this phrase. One alternative is "taking a headcount," which essentially means the same thing. Another option is to say "tabulating attendees," which adds a more formal tone to the task. Similarly, "calling the roll" is often used in educational settings to refer to taking attendance. Finally, "checking in," "registering," or "recording attendance" are additional synonyms that can be used when referring to the act of counting heads.