Scarwood Reach works a little differently from the other zones as there is an NPC that will tell you which rares are up! There will be different rares up on different shards, so be sure to check them all!

There is a daily quest to kill 5 rare creatures called: Pursuing Prey.
When you kill a rare creature you will receive a quest item which you then right click to open up the quest to hand the item in. When you hand in these items you will receive a hunting token which goes towards the daily quest to collect 5.

The Defiant NPC to pick up the daily quest from is at /setwaypoint 3683 4421
The Defiant NPC to tell you which rares are up is at /setwaypoint 3690 4396
The Guardian NPC to pick up the daily quest from is at /setwaypoint 3134 3887
The Guardian NPC to tell you which rares are up is at /setwaypoint 3148 3873

Click the NPC and underneath his ‘I’d like to buy something’ selection there will be a list of rares that are up, clicking the names of the rares will give you a description of that rare and a hint of where to find them.

The NPC will require you to complete the first hunt quest before you can then pick up the daily, and only once you pick up the first daily will you then be able to ask the other NPC which rares are up!
You will only be able to see which rares are up while you have the daily active in your questlog, so if you plan to spam loads of rares in one day then you will want to keep the daily in your quest log, don’t hand it in!

If the shop opens up straight away when you click the NPC then it means no rares are up at that time.
If the NPC just has ‘What’s next..’ as a chat selection then it means you have handed in the daily hunting quest and he wont tell you which rares are up until the next reset (daily).