ZSH by default emits a terminal bell on auto-completion which can be irritating.
unsetopt LIST_BEEP
See https://blog.vghaisas.com/zsh-beep-sound/
LIST_BEEP Beep on an ambiguous completion. More accurately, this forces the completion widgets to return status 1 on an ambiguous completion, which causes the shell to beep if the option BEEP is also set; this may be modified if completion is called from a user-defined widget.
A related setting is:
HIST_BEEP Beep in ZLE when a widget attempts to access a history entry which isn’t there.