I want the list of all those Pokemon that give ev in speed but that are also in pokemkon hordes only
Here you have the full list of ALL Pokemon that give Speed Evs:
http://www.serebii.net/pokedex-xy/speed.shtml
Here you can find all hordes was you want and their respective route:
http://www.serebii.net/xy/hordes.shtml
(EDIT) In the hordes link you can find the Pokemons you can find in hordes/locations/evs given.