Idea:
Quickly copy a Youtube or other video site, and open in the MPV media player.
Plugins:
Vim Vixen for Firefox
https://addons.mozilla.org/en-US/firefox/addon/vim-vixen
Surfingkeys for Chrome/Chromium browser
https://chrome.google.com/webstore/detail/surfingkeys/gfbliohnnapiefjpjlpjnehglfpaknnc?hl=en-US
Script:
#!/bin/bash
##...