This plugin adds an option to each folder's drop-down menu so that all requests within can be ran at once.
The original code was taken from https://support.insomnia.rest/article/26-plugins#folder-actions and the author is Greg Schier, creator of insomnia.rest, so all credits to him! All I did was create a repository, package it up and publish to npm.
This plugin is published in npm. To use it you can install it from your insomnia.rest client by going into Preferences -> Plugins and entering the package name insomnia-plugin-run-folder then click "Install Plugin".