If your NUETRAL or better with Netherwing Dragonflight, you can mine Nethercite Deposit or collect Netherdust Bushes south east edge of Shadowmoon Valley.
They are relatively easy to find and spawns quite fast. This stays yellow till 410, and becomes gray at 426-440.
This area should be practically deserted. There's a handful of rich Adamantites and more regular Adamantites for your collecting too. Also various herbs for your taking!
Spending time at least an 15 minutes here will probably save you days in leveling these gathering skills... best investment you could ever do!
by Grass