TubeBuddy can highlight the following important commenters within your comments.
Recent Subscribers
If you have a Legend level license, TubeBuddy tracks your new subscribers and if any of your most recent 1,000 subscribers have left a comment on the YouTube comments page, they will be highlighted. Please note that some people hide who they are subscribed to and in those cases, they won't be highlighted.
Patreon Supporters
After linking your Patreon account on the Integrations Page, your Patreon Supporters will be highlighted within your comments. Please note that you need to periodically refresh your linked Patreon account at https://www.tubebuddy.com/integrate/patreon