Read from the World of Warcraft client build files.
Where Dominating Gladiator's Tabard Fits
Items Numbered Next to Dominating Gladiator's Tabard
Blizzard numbers items as they are created, so the named items next to ID 149446 (149441 to 149451) were usually added in the same batch as Dominating Gladiator's Tabard: the same quest line, zone, vendor or reward set.