Push-to-Talk, but works at Pulseaudio level, so it works on all apps at once. It has a single global "walkie-talkie button" that mutes and unmutes the microphone (I use the Windows key).

Very useful for remote work:

- you can type on mechanical keyboards during calls without annoying your co-workers

- if you move away from your computer for a while, the microphone will be muted, so you avoid background noise and embarrassing situations

- if you un-mute the microphone without touching the trigger key, it will remain un-muted. In case you want to have longer conversations. Touching the trigger key will mute it again