Titles are account-wide.  Pets and mounts are account-wide.  Toys and heirlooms are account-wide.

But you know what I REALLY want to be account-wide?

Tabards.

Tabards.

Because as is I have two characters with Tabard of the Argent Dawn but my current main doesn’t have it.  Just my luck, right?  But yeah, I would LOVE to be reunited with it.  I’ve already been reunited with my Vampiric Batling and Spirit of Competition.  Tabards next?  Please Blizzard?