Since I've played only BC and MoP, I haven't been able to get nice-looking sets for transmogrification. Recently I discovered that there are more set vendors ("Legacy" Vendors) than the ones in Stormwind or Orgrimmar.
The known vendors I know are:
- Stormwind (Honor and Justice Vendors, Champion's Hall and SI:7)
- Tanaris (Honor Vendor, several PVP sets, up to Relentless)
- The Argent Tournament Grounds (Justice Vendor, only 1 set)
- Dalaran (Justice Vendors, some PVP sets for Justice, Tier Tokens, Heirlooms)
- Isle of Quel'danas (Honor and Justice Vendors, some PVP sets)
There must be other legacy vendors that can give you some sets for transmogging for either honor or justice. Do you know the location of the remaining ones?