My idea of DDdos and AGMence sets
Gyarados@Leftovers
Dragon Dance
Waterfall
Return
Taunt
I think this is the best Gyarados set. Jumpman's set, the most popular nowadays, (Ice Fang + EQ + DD + Taunt), doesn't hit hard, pokes like Rhyperior (Rock Slide hits hardly Gyarados, yeah, Earthquake...