Veil for Mac
Veil blurs background application windows while one app stays clear. Use Frontmost Window mode to follow focus, or Cover App to lock clarity on a slide deck or IDE for an entire-screen share. You turn Veil on manually before Zoom, Teams, Meet, or a recording—it does not watch for meetings.
Curtainly
Curtainly drops a privacy curtain over your Mac during screen sharing: it hides wallpaper and desktop icons, auto-hides the Dock, turns on Do Not Disturb, mutes alert sounds, and turns off AirDrop receiving, plus hides the apps you list. Per curtainly.tech, it turns on by itself when you share in Zoom, Microsoft Teams, Slack, or Google Meet; for anything else you press ⌃⌥C. It cannot tell when you share a single browser tab, or share from Safari or Firefox.