Sure, almost all MMOGs have emotes. They've been there forever. But much like the incredibly involved character creator, City of Heroes boasts a wide range of very silly and fun choices, perfect for those who love to add in that little oomph when role-playing or just messing around with friends. Also, unlike the fire-and-forget-it emote development of many other MMOs, the City of Heroes developers continue to slowly add new emotes in to the game, both through patches and microtransaction packs. Some are easy to find through the chat menus, while others are a bit off the beaten path, and short of hunting down a listing, you may not have seen them all.
For those who haven't ever experienced the wide range of City of Heroes emotes, I've compiled a gallery of some of my personal favorites. That said, this gallery is nowhere nearly the entirety of the emotes in the game. In researching this, I realized there were quite a few I hadn't even seen yet - despite playing CoH for a couple of years now! There are also a few emotes that have multiple /em commands to activate.
That being said, there is really no substitute for seeing them in action. So, if you've been considering trying on some tights, there's no time like the present!