The best replacement for buzzer is piezo.

The best alternatives to buzzer are rated as following:
★★★★★  piezo
★★★★★  speaker
★★★★  transducer
★★  doorbell
★  electric bell

Your alternative for buzzer is not listed? Suggest!
Speaking about buzzer, one probably shouldn't forget about timer.

Other search terms related to buzzer and their ratings are:
★★★★★ timer
★ intercom
★ led light
strobe
pilot light
You have in mind a companion for buzzer and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of buzzer in all years. Click on graph for more.
buzzer
piezo
speaker