Here is a complete list...
Moltres - Sky Attack
Mewtwo - Psystrike
Lugia - Aeroblast
Ho oh - Scared Fire
Latias - Mist Ball
Latios - Luster Purge
Groudon - Precipice Blades
Kyrogue - Origin Pulse
Rayquaza - Dragon Ascent
Jirachi - Doom Desire
Deoxys - Psycho Boost
Dialga - Roar of Time
Plakia - Special Rend
Heatran - Magma Storm
Regigigas - Crush Grip
Girtiana - Shadow Force
Cresselia - Lunar Dance
Manaphy - Heart Swap
Darkrai - Dark Void
Shaymin - Seed Flare
Arceus - Judgement
Victini - Searing Shot
Cobalion - Scared Sword
Terrakion - Scared Sword
Virizon - Scared Sword
Reshiram - Fusion Flare, Blue Flare
Zekrom - Fusion Bolt, Bolt Strike
Kyurem - Glaciate
Black Kyurem - Fusion Bolt, Freeze Shock
White Kyurem - Fusion Flare, Ice Burn
Keldeo - Scared Sword
Genescet - Techno Blast
Xernas - Geomancy
Yvetal - Oblivion Wing
Zygrade - Land's Wrath, Thousand Arrows, Thousand Waves, Core Enforcer
Diancie - Diamond Storm
Hoopa - Hyperspace Hole
Volcanion - Steam Eruption
Tapu koko - Nature's Madness
Tapu fini - Nature's Madness
Tapu bulu - Nature's Madness
Tapu lele - Nature's Madness
Solgaleo - Sunset Strike
Lunala - Moongeist Beam
Kartana - Cut
Necrozma - Prismatic Laser
Magerena - Fleur Cannon
Well actually Signature Move means only one Pokemon can learn this move in any one generation by any one method.