Boss keys[1] should be standard for every website. The March Madness[2] one for example. There are some good ones developed for Reddit to look like Outlook[3], shell [4], etc.

[1] https://en.wikipedia.org/wiki/Boss_key

[2] https://www.ncaa.com/march-madness-live/boss

[3] http://pcottle.github.io/MSOutlookit//

[4] https://redditshell.com/