Togekiss! Squeeeeee! While this pokémon may be endangered due to strife in the world, it is still an amazing pokémon that catapulted the togepi line into the spotlight. Rivals Jirachi and Shaymin-Sky for best abuser of Serene Grace in the game, and is certainly the strongest user of it. Being a former normal type turned fairy, its has the excellent movepool of the former combined with the amazing typing of the latter. Ignore at your own risk.
A Nasty Plot
Tokegiss
Ability: Serene Grace
Item: Leftovers/Sitrus Berry/Life Orb/etc.
-Nasty Plot
-Thunder Wave
-Air Slash
-Roost/Dazzling Gleam/Aura Sphere/Flamethrower
EVs: 252 HP/252 Speed/4 SATK
Nature: Modest (+SATK, -ATK)
Simple premise: Find an opportunity to setup a nasty plot, Thunder Wave an opponent, and whittle them down with Air Slash, with the combined Flinch and Paralysis rate ensuring that the opponent only has a 30% chance to move. Last move is up due to personal preference. Roost is great if you are using Life Orb to shrug off residual damage, Dazzling Gleam is for STAB coverage, Aura Sphere and Flamethrower deal with select Steel types who resist Air Slash. (Aura Sphere also hits Rock types, while Flamethrower gets Celesteela and Scizor on the switch). EVs are to Maximize Bulk and Speed (for flinch chance), so you are reliant on Nasty Plot to deal significant damage.
Item choice is rather fluid as well. You can choose Leftovers, or recovery berries for bulk, or Life Orb/Sharp Beak/Flynium Z for damage.
Ground type partners like Hippowodon, Mamoswine, Diggersby, and Garchomp are amazing, because they counter electric types who wall this set HARD (Immunity to T-Wave, high base speed, and resistance to Air Slash), as well as being an answer to Rock, Steel and Poison types who all worry Togekiss. They in return enjoy the anti Grass protection, as well as Togekiss' ability to leave the opposing team a paralyzed wreck.
A Supporting Kiss
Tokegiss
Ability: Serene Grace
Item: Leftovers/Sitrus Berry
-Wish
-Heal Bell
-Tailwind/Yawn/Air Slash/Thunder Wave/Protect
-Tailwind/Yawn/Air Slash/Thunder Wave/Protect
Nature: Bold (+DEF, -ATK)
EVs: 252 HP/252 Speed/4 SDEF
Cleric Togekiss. Wish and Heal Bell to recover what ails your team, with the last move up to personal preference. Tailwind and Thunder Wave are good speed support options. Yawn forces shuffling and can be good for mind games when combined with Wish. Protect for the Protect/Wish Combo. Air Slash to avoid being Taunt bait. Serene Grace is the preferred ability again. Partially for Air Slash, partially because it cannot screw you over unlike Hustle. EVs are to Maximize speed and bulk again, to ensure that Tokegiss gets its moves off while surviving.
Other Options
You could do a gimmick set with Super Luck and a Scope Lens to ensure 50% crit Chance on all of Tokegiss' moves, but since Tokegiss lacks Focus Energy or any viable high crit chance moves... well that's why its a gimmick set.
-Trick -Always a Fun move no matter who gets it.
-Reflect/Light Screen -Togekiss can Dual Screen as well.
-Psycho Shift -This is an interesting move. With this Togekiss, can pass around Burns when combined with the Flame Orb as well as absorb Toxic and Thunder Waves to pass around as well. Better Accuracy than Will-o-Wisp, Toxic and Thunder Wave too. Gimmick.
-Psychic/Shadow Ball -Other special attacking options. Psychic is good for Poison types... Yeah Shadow Ball only provides extra coverage.
-Telekinesis -Fun move in Doubles. Combine with an Inferno or Zap Cannon user for oodles of pain for your opponent. Gimmick.
-Attract/Sweet Kiss -Stack with Togekiss' existing combo to reduce foe to acting 15% or 17% chance of acting respectively. The unreliability of the former and the poor accuracy of the later means that this is still nothing more than Gimmick.