Just a few days ago @lloydi also shared a bunch of bookmarklets…
Visually hidden: https://a11y-tools.com/bookmarklets/#visuallyhidden
ARIA hidden: https://a11y-tools.com/bookmarklets/#blackout
Live region watcher: https://a11y-tools.com/bookmarklets/#blackout
Nod murder: https://a11y-tools.com/bookmarklets/#nodekiller
Selector²: https://a11y-tools.com/bookmarklets/#selectorselector