It's kind of like Alfred for sketch. If there is a symbol or icon I need I can start typing it's name and I insert it without having to go through our design system's file tree. It has been a godsend for speed and I don't think it would be possible for me to work without it.
I was forced to switch to it and I miss all of my plugins, but I have to say the sharing and commenting features are so much more useful/seamless than the Sketch/Zeplin combo I used to use. So even though it’s a worse design tool, my productivity is better because of the seamless collaboration.
We use Sketch with Invision—that works well enough for us. Although I wish Invision would allow me to @ myself on comments so I get an email reminder me to fix things I've found in review.
1 minute of searching also reveals a plugin called "Figma Walker" which, as the name implies, is an attempt to copy the exact functionality of Sketch Runner.
Not quite sketch runner, but part of the way there.