ORAS OU Ranking Tier List
(In alphabetical order)
S Rank: Reserved for Pokemon that are the pinnacle of the OU metagame. These Pokemon are able to perform a variety of roles very effectively, or can just do one extremely well. Their use has low risk involved and high reward exerted. Pokemon in this rank have very few flaws that are patched up by numerous positive traits. These Pokemon define the metagame.
S Rank
Altaria (Mega):Hard check special sets and stone wall physical sets.
Clefable: it can't do much to you.
Keldeo: lol don't bother.
Landorus: Haha this roflsfomproflstomps you.
Metagross (Mega): hammer arm is it's best bet and that hardly 3hkos. Your earthquake outdamages hammer arm too
A Rank: Reserved for Pokemon that are fantastic in the OU metagame, and can sweep, support, or wall significant portions of the metagame. These Pokemon require less support than most others to be used effectively and have few flaws that can easily be compensated for when compared to their positive traits. These Pokemon exert a strong presence in the metagame.
A+ Rank
Azumarill:hates superpower from banded but you stone wall belly jet.
Bisharp: Aside from low kick it's not scratching aggron.
Charizard (Mega-X): don't go aganst this.
Diancie (Mega):one time check at best.
Garchomp:fatchomp can't hurt all that much and you avalanche it.
Gengar:see diancie.
Gliscor:This tickles you to death, avalanche kills it if it attacks.
Gyarados (Mega):Loses.
Heatran:Offensive ones win but defensive hates earthquake.
Landorus-T:swords dance wins but you can check other variants.
Lopunny (Mega):252 Atk Mega Lopunny High Jump Kick vs. 252 HP / 16+ Def Filter Mega Aggron: 141-168 (40.9 - 48.8%) -- guaranteed 3HKO. Be careful of adamant ones and power up punch variants.
Latios: Defog + 3 attacks loses but cm + draco overwhelms aggron. It hates t-wave though.
Manaphy: you lose
Sableye (Mega): see manaphy
Scizor (Mega):you wall it hard. Fire punch it.
Talonflame: You lose if it has wisp but you can beat other variants or if you have stone edge.
Thundurus: You lose to nasty plot but check mixed and 3 attacks plus utility ones.
Tornadus-T:one time check at best.
A Rank
Alakazam (Mega): can take a focus blast and cripple it. Heavy spam ohkos after rocks.
Charizard (Mega-Y): see landorus-i
Excadrill: You can't beat adamant sand rush ones but jolly ones you check
Ferrothorn: It can annoy you but if you have fire punch you win.
Gardevoir (Mega): Takes a focus blast and ohkos with heavy slam.
Hippowdon: lol.
Latias: same as latios but it struggles more.
Latias (Mega): stored power wins if it has alot of boosts. Reflect type beats you if no fire punch.
Manectric (Mega): it will overheat + volt switch to kill.
Rotom-W: you lose.
Slowbro:hard walls you.
Starmie: depends on the set. You can't switch in.
Tyranitar: you hard check it
Venusaur (Mega): doesn't threaten you
A- Rank
Aerodactyl (Mega): eats up any hit.
Celebi: you can beat most without earth power.
Gyarados: don't try.
Jirachi: lol you stone wall it.
Klefki: same here but it still supports its team.
Kyurem-B: lose to earth power.
Mamoswine:one time check.
Mew:will-o-wisps and stalls you out
Pinsir (Mega):you win even at +2
Politoed:you lose.
Raikou:volt switches away.
Serperior:really hard checks this
Skarmory:nope
Slowbro (Mega):see regular slowbro
Volcarona: you can win if it decides to set up and stone edge It.
Weavile: you check it rather hard.
B Rank: Reserved for Pokemon that are great in the OU metagame. These Pokemon have more notable flaws than those above them that affect how they function in the tier. Their positive traits still outshine their negatives, but they require a bit more team support to bring out their full potential. These Pokemon exert an above average presence in the metagame.
B+ Rank
Breloom:sash ones aren't doing much with mach punch.
Chesnaught:it can stall you out.
Diggersby: beats you.
Dragalge: can't switch into specs.
Dragonite:you can beat this really easily
Gallade (Mega):depends if boosted or not.
Heracross (Mega):ha ha ha...
Hydreigon:one time check
Kabutops:you can beat this rather well
Kingdra:good luck
Magnezone: magnezone can't reliably trap it as most carry earthquake.
Suicune:same as slowbro
Swampert (Mega):lose
Tentacruel:relies on scald burns to win.
Terrakion:only takes 1 close combat.

Togekiss:you get flinched to death
Victini:you lose.
B Rank
Amoonguss:not threatening to aggron
Azelf:mostly used as a lead.
Beedrill (Mega):you hard wall it
Chansey: can't threaten you but it will stall you out.
Conkeldurr: win vs assault vest but die to sheer force ones
Crawdaunt:aggron checks I.
Cresselia: hardly threatening to aggron.
Empoleon: you can win if you have earthquake
Gothitelle:can't hurt you
Hawlucha:only threatens at +2
Quagsire: same deal with other bulky waters.
Omastar: try again
Sceptile (Mega):you win
Scizor:same deal as mega scissor.
Scolipede:can't hurt you whatsoever
Sharpedo (Mega):you can beat this well.
Slowking:same as slowbro
Zapdos:you lose as pressure drains stone edge pp.
B- Rank
Alakazam:same as mega zam
Alomomola:see suicune
Feraligatr:can't threaten you too much plus thunder wave cripples.
Garchomp (Mega):lol
Houndoom (Mega):lol
Lucario:depends if boosted or not
Mandibuzz: hardly touches you.
Medicham (Mega):lol
Reuniclus:depends if it has focus blast or shadow ball
Sylveon:you win
Tangrowth: can't hurt too much

Toxicroak:dependant on if boosted.
Tyranitar (Mega):checks it well
Tyrantrum:same as mega ttar