One of my friends pointed out an ACT plug-in, [EQ2] What Rune.This allows you to /con a mob and get an ACT call that tells you what red belt rune you need for that mob, or type /rune {mobname} to get it. How handy, right? Instead of me pawing through the Post-It notes on my monitor trying to find which rune for what mob. Only problem is, it appears as though the database only has VoV. I know these runes: The Delving Departed (Foundation of Knowledge) - fear rune The Haunting of Tualanan (Terrene Threshold) - fear rune Tawerek (Takish Badlands: Overgrowth) - stifle rune Khadra Chatt (Blood and Sand) - stun rune Quartermaster Hamid (Blood and Sand) - stun rune But dang if I know what other RoR mobs need which immunities. If you know any of them and will share here, I'll contact the plug-in author and ask to have them added.
what we really need is a UI addon that allows you to leave yourself target-specific notes in-game. kind of just like "Bio" text box on your character tab. then u don't need something so narrow as "what rune" addon notes don't need to be saved anywhere online, just local drive. then next time u target a mob and look at your addon window, it simply pulls up your notes for it if any. the addon can come with a pre-canned file that u have an option to import as a starting point, that can contain immunity rune info. but i've asked around for this on and off probably for 5 years on UI addon forums a while back to no avail. so i doubt my dream will come to fruition.
Here's the GitHub to the plugin. Skyfire.Reapp is the creator it seems. And there's a PR for adding RoR stuff. Here's a page that shows how you can use it.