Ring4 Meeting - Dead simple video conferencing - free, in browser
John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads
Stork.ai - AI-Based Collaboration for Hybrid Teams. Rich media messaging, advanced video and voice conferencing, auto-transcribing and screen sharing. Serendipitous meetings at the water-cooler with your human and AI teammates.
Unsplash Wallpaper - Gorgeous wallpapers on your Mac
openmeet - Account free video conferencing with a rooms component that lets you use VC within a physical meeting room. The server can also be hosted in your own cloud for extra privacy/security.
Wallcat - Enjoy a new, beautiful wallpaper, every day.