General:
* All
* Each
* Everybody
* All people
* Every single person
* All of us
* The whole world
More specific:
* All of humanity (if referring to people as a whole)
* All mankind (if referring to men)
* All humankind (if referring to both men and women)
* Every soul (if emphasizing the individual)
* All hands (if referring to a group working together)
* Every Tom, Dick, and Harry (if referring to a general, undistinguished group)
The best synonym to use will depend on the specific context of your sentence.