Blizzard temporarily removed the heirlooms that were previously sold for Justice Points, due to justice points going away. For a short while the PTR had them for sale for gold, but they changed their minds and said that they will re-release them later with some other way of obtaining them.

You can still get the guild heirlooms like you already found, and there's also some PvP heirlooms available for honor, and lastly there is the Argent tournament, but it will take a while to get those.

On sundays you can try for the fishing extravaganza for a ring, but theres usually a lot of competition, and the ring only provides 5% bonus exp.