Rare monsters are very important, they drop good gear, give achievements and might be the best hunter pet.
I used to use _NPCSCAN and SilverDragon, but they all feel strange and have some problems, such as you need to clean cache.
So I wrote a Addon for myself, and use it for years.
Now, I noticed _NPCSCAN stopped update, and can't find rares in path 5.2, but my addon can.
After kill at least 3 rare each day on isle of thunder, I decide to share my addon.