Rift Achievement:Big Game Hunter  

Talking to the Hunter NPCs at Perspice (for Defiant) & Kain's Command (for Guardians), while on the Quest for Hunter Tokens, will allow you to see which rare mobs are up, and where they are found. Check back frequently because there are ALWAYS rares up in Scarwood. When one dies, another spawns.

These are also an excellent way to get Notoriety. As each token gained rewards a large amount, and turning in all 5 tokens is even more. Making the rep easily capped.

Check out Rare Mob Compendium for detailed information on known spawn locations. Also see A Hunter's Guide to Scarwood Reach.