Plaguebats (marked BLUE on the map) - These Plague-affected beastly flying creatures roam southern parts of the Eastern Plaguelands. Slaying them will provide you with a lot of Vendor Trash Items (Evil Bat Eye, Bat Ear, Sleek Bat Pelt, and Large Bat Fang), Wicked Claws (used in Leatherworking and Blacksmithing Recipes), and maybe some 16 Slot Bags. Bats can also be Skinned for Rugged Leather, Thick Leather, Thick Hide, and Rugged Hide, so Skinning Profession is recommended for this Spot. Plague Bats have access to the Terrifying Screech Ability, so they can get annoying at times, especially for melee Classes, but are a great source of Gold nevertheless. Recommended Level - 53+.
Even though the guide was developed with a hunter, the guide can be followed by any class. Except you have to do your class's quests which aren't a whole lot. I do have full intention to make my guide friendly with all classes in the future by listing all of their steps as well. There will be a toggle that allows you to show which class's steps you want to see in the guide. But this is coming later.
If possible, avoid purchasing Gear from the Auction House - Ideally, you should be able to achieve level 60 without buying anything from the Auction House. This way you will save Gold, but possibly make leveling a bit harder for yourself. If you badly require an Item upgrade, and the suitable Item is available on the Auction House for a low enough price - buy it, but only if you think that the investment will pay for itself in one way or another (the main exceptions to the Auction House ban Rule are Weapons and Wands, as they make leveling much faster, and pay for themselves by allowing you to chain-kill more mobs without Eating and Drinking, which saves Gold and time).
WoW: Classic is scheduled for August 27 (technically August 26 if you're in the Americas). The soonest that you can play it is starting in May, during Blizzard's scheduled stress tests. To opt-in you must have an active subscription on your Battle.net account. If you do, go to Account Management and select the Wow Classic beta. Keep in mind, there will be level caps during the test. The schedule is as follows:
Whelgar's Excavation Site - This Dwarven excavation site was overrun by Raptors (Mottled Scythemaws and Mottled Razormaws). These reptiles are a great source of Medium Leather (you should have Skinning Profession if you want to farm here, as a very large portion of income that comes from this spot is acquired by Skinning Raptors). They also drop some Vendor Trash Items and Raptor Eggs (these are convenient, as a Cooking Recipe for them comes from a Quest that is located just above the Site) that can be used for Leveling up Cooking Skill. However, the best part about this spot is that both Raptor types present here drop level 19 Twink Gear (Feet of the Lynx, Sentry Cloak, Redbeard Crest, and Twisted Chanter's Staff) that will achieve astronomical prices at the later stages of the Game (drop rates are very low, so some RNG is involved, sadly). Recommended Level - 25+.