I want to give you 3 items that will be highly needed in Phase 2 for profession leveling in WoW Classic Season Of Discovery. These are items that you can farm now in Phase 1 and stay ahead of the curve in terms of leveling your professions and get some important items up on the auction house as soon as next phase releases.
As I stated, you can farm all these items now. However, some are easier to farm than others. I didn't want to take multiple items for the same profession, so these are the items for 3 main crafting professions: Blacksmithing, Leatherworking, and Tailoring.
Bring plenty of WoW SOD Gold will help you a lot when farming these items.
Blacksmithing: Iron Ore
For blacksmithing, the item you want to stockpile and put your focus on is Iron Ore. You will need a truckload of iron bars in Phase 2 in order to level your Blacksmithing, and starting to farm some now would definitely go a long way in terms of leveling Blacksmithing to 225 in the next phase.
Iron Ore is arguably the hardest item to farm on this list due to its limited spawn rate. However, I found most success in farming this in Thousand Needles, as there are multiple fast spawn points there. However, the competition can be very fierce, not to mention the higher-level mobs that prowl the area.
Leatherworking: Heavy Leather
For leatherworking, we have an obvious one, that being Heavy Leather. Heavy Leather is the next tier of leather needed in order to reach the golden rank of 225 in Phase 2. You can easily farm this item now. They're currently going for around 5 to 6 silver apiece on my server. As you progress further to the next set of leveling zones with mobs more around the Level 30 mark, we'll be seeing a lot more of these dropping, so the price will drop as well.
However, you will need a buttload of heavy leather to reach your next rank of 225 in Leatherworking. So having as much of it as you can on hand to start crafting right out of the gate on Phase 2 launch is a very good idea, as I'm sure that most people won't be getting Leatherworking maxed straight away. So, a lot of the items available from Leatherworking will probably be in high demand as soon as the phase launches.
Tailoring: Silk Cloth
Our final item for Tailoring is Silk Cloth. Tailors will need an absolutely insane amount of Silk Cloth to blast their way to rank 225 in Tailoring next phase. Silk Cloth is very easily farmed right now, with multiple locations having a very good mob respawn rate. You should be able to farm out a decent chunk of the amount you need right now. If you're unsure of where to farm Silk Cloth, you can search for some good farming spots. However, all of these spots are heavily contested, as these items are all in high demand.
That wraps up this quick guide. Bear in mind that farm locations for these items mentioned are bound to be heavily contested, as people smarter than me have already started these farms and getting their banks stuffed with these materials for Phase 2.