Jan 22, 2016, 08:33 AM
Rayquaza is currently the 7th most used Pokemon (4th Legendary behind Groudon, Xerneas and Kyogre) on Battle Spot VGC '16 so I wouldn't consider him an ''underdog'' legendary even though I don't think he's really good. Mewtwo does not appear in the Top 12 of most used Pokemon but he's probably not that far (probably in Top 20). If you want to talk about legendaries almost no one is going to use, my vote would go to Yveltal, Kyurem-White or Zekrom. All three of them are really solid. Yveltal can be a mega tank, Kyurem-White hits like a truck without any set-up and Zekrom can scare popular Pokemons like Primal Kyogre off the field pretty easily.