HackerBrain and HackerTrain.

https://greasyfork.org/en/scripts?by=1628132

With Hackerbrain, I can easily skim top comments of stories with minimal mouse and eye movement. (using orange, green and red buttons next to each story after pressing -- )

As a script, almost no latency. Keeps track of what I've already seen too. Can also completely ignore it and HN appears and functions virtually unchanged.