Outside of orgrimmar you can find them dueling like how alliance duel in front of stormwind/goldshire
In pandaria you can hang around the shrine of two moons, pang's stead where there are always some levelers, and the arboretum where people are trying to get the dragon mount. You can try timeless isle at huolon's spawn but they are usually fully geared.
You can also camp the entrance to the halls of origination in uldum where there is usually a steady flow of bots that you can kill or camp the taxi at cosmowrench in outland which gets a good amount of traffic. The bots are usually rogues though so I don't think they'd help with getting tauren kills.
You can also try camping the entrances of popular instances like icc, ulduar, caverns of time, and firelands.
That's all I can think of at the moment besides ashran, good luck!