My first Uber team, so far it has been working quite well for me. Let me know what you think:
*This is not a defensive team this is an all out attack and finish the job quickly team*
Gengar
Gengarite/Levitate
Hypnosis
Nightmare
Hex
Dream Eater
4HP/252SpA/252Spd
Timid Nature
Gengar's sole purpose is to be a pain in the ass lead. With maxed out speed it should hopefully attack first. His mega evolution gives him the ability shadow tag which makes it so your opponent cannot switch out. This helps make sure the sleep clause mod doesn't screw you on Hypnosis. Combined with Nightmare, Hex, and Dream Eater, as long as Hypnosis actually hits it's target, Mega Gengar is hard to beat.
Yveltal
Life Orb/Dark Aura
Dark Pulse
Oblivion Wing
Sucker Punch
Steel Wing
4HP/252SpA/252Spd
Mild Nature
So, Yveltal has great stats to be a mixed attack sweeper. Dark Pulse, Sucker Punch and Oblivion Wing give STAB and Oblivion Wing helps restore HP, eliminating the need for a move like Roost. Steel Wing is for type coverage against Fairy Types (Xerneas mainly).
Xerneas
Power Herb/Fairy Aura
Moonblast
Focus Blast
Geomancy
Psychic
252HP/252SpA/4Spd
Modest Nature
Kind of basic Xerneas move set. Geomancy for setup and Moonblast for STAB. Focus Blast and Psychic for type coverage against Steel and Poison types.
Rayquaza
White Herb/Air Lock
Extreme Speed
Dragon Pulse
V-Create
Ice Beam
252Atk/252SpA/4Spd
Lonely Nature
Who doesn't love Rayquaza. Extreme Speed for priority. Dragon Pulse for STAB and has better accuracy than Draco Meteor and doesn't hurt your SpA either. V-Create for just a great move. White Herb helps counter the stat loss from V-Create once, so using it multiple times doesn't hurt you too much. Ice Beam for type coverage.
Genesect
Shock Drive/Download
Techno Blast
Extreme Speed
Bug Buzz
Gunk Shot
4HP/252Atk/252SpA
Hasty Nature
Mixed attacker. Techno Blast with Shock Drive for water type coverage (this team has none otherwise). Extreme Speed for priority. Bug Buzz for STAB. Gunk Shot for coverage against Fairy types.
Blaziken
Life Orb/Speed Boost
Blaze Kick
Brave Bird
Brick Break
Poison Jab
4HP/252Attk/252Spd
Adamant Nature
Physical Attacker. Blaze Kick and Brick Break for STAB. Poison Jab to counter Fairy types.