Grave Moss

About 19s 97c on Beta · Horde (5 hours ago), 1s 22c on Beta · Alliance (23 hours ago), and 18s 0c on Beta · Horde (24 hours ago), from player scans. A vendor pays 25c, so the auction house pays 75.9× more.

6 recipes: Elixir of Coalesced Regret, Spellblasting Potion, Shadow Protection Potion, and 3 more.

No. It is in Classic Era too, with the same item level, vendor price and stack size.

Sell it on the auction house. After the 5% cut a stack of 20 brings about 3g 79s there, against 5s 0c at a vendor.