5th champion emote. Clapping.
Posting this on this board, since it has to do with something a champion can do.
I feel like each champion should gain the ability to clap. Because while laughing seems to have its place, I think a clap could really be a nice addition. Using it at the right time could be like you are congratulating the person who did a really nice play. Like a Lucian getting a penta with his ult or Soraka healing someone on the brink of death. Or it could be used sarcastically when a Blitz misses a pull or when an Ezreal/Jinx completely miss their ult. And I don't think it'd be too much of a hassle to add.
And for characters who don't have hands there are ways around that. Skarner and Cho'gath could clamp their pincers. Vel'koz could make a completely robotic clapping noise verbally. Kog'Maw could smack its' tail against the ground. And Anivia could smack her wings against each other while flapping.
It just seems like something that could be entertaining to add.