Currently the only thing I'd want to nominate to ubers is Manaphy, but since it's already a suspect due to the simple majority last round, I see no need to write up something big for it. I will say that I really feel Manaphy is the problem, and not Drizzle though. There's usually a way to play around the Swift Swimmers, but against Manaphy, it's honestly able to checkmate you a lot of the time with the HydroRest. Tail Glow wrecks Stall, and Calm Mind wrecks offense. Both can wreck balance. None of the other Rain abusers can boast the ability to steamroll through each playstyle with little to no effort.
However, one thing I would like to do is nominate Deoxys-N for OU. Deoxys-N had a very unfair testing environment where he was basically a blanket ban with Deoxys-A for being an offensively-based Deoxys. I know people aren't going to admit it, but it's pretty obvious that people barely played against it last round, or else they would have seen that it sounds good on paper, but is actually kind of hard to use in practice. I honestly don't know where people got the idea that he was even slightly overpowered, because he's really not.
Unfortunately, the difference in power is really noticeable from Deoxys-A, especially when the majority of the time, you're firing off nonSTAB Special moves with 80-95 BP from 399 SpA (518 with Life Orb). This may seem high, but without STAB, it really doesn't hit that hard. If he carries STAB, this lowers his coverage, which he really needs if he actually wants to sweep.
People were saying that "you use him the same way as Deoxys-A, just fire off Psycho Boost." This can be risky, however, and because of his lower attacking power compared to Deoxys-A, this isn't a foolproof strategy, especially when standard has the following pokemon, who can act as hard counters/checks to Deoxys-N:
Steel/Psychics - (Jirachi, Metagross, Bronzong) - Self-explanatory
Psychics with Recovery - (Rankurusu, Celebi, Mew, Deoxys-D, Latias) - All can come in on Psycho Boost and Recover the hit off, while not being able to kill on the 2nd hit with Shadow Ball/Ice Beam (Latias and Celebi) due to -2 SpA.
Steels with Priority - (Kirikizan, Scizor) - Deoxys-A's Psycho Boost may have been able to do over 50% to Scizor, but Deoxys-N's can't due to the power drop. Bullet Punch still OHKOs (or Scizor sets up, even moreso with Rain ruining any utility HP Fire may have had). Psycho Boost doesn't even affect Kirikizan, and while Superpower will OHKO (hint: this is a check, not counter), Kirikizan will OHKO with Sucker Punch first. If Deoxys-N is carrying ExtremeSpeed, Kirikizan can set up a Sub in its face and make life difficult with SD, and his attacking moves.
Wobbuffet - Pretty much anything Deoxys-N does to Wobbuffet will result in a OHKO in return with a countering move.
"But Deoxys-N can just switch out and come in again to fire off another hit!"
Sorry, but I didn't even mention the things that would be solely revenge-killing Deoxys-N (ie. the Choice Scarfers that can hit over 438 Speed). I didn't mention Chlorophyll/Swift Swim/Sand Throwers who are all faster than Deoxys in their respective weather and can OHKO him with a whole ton of shit. With the exception of Wobbuffet, this entire list is stuff that can set up shit to utterly punish Deoxys-N for switching out.
Jirachi can set up his Sub + TWave strategy, or Sub + Calm Mind, or just start Calm Minding up right off the bat. Metagross can set up Agility and possibly sweep your team. Bronzong can set up Trick Room and possibly wreck your entire team if it's offensive, or just sweep it with Gyro Ball if it's HO. Rankurusu can set up Calm Mind or Trick Room, both of which it can destroy teams with. Celebi can set up Calm Mind, Nasty Plot, or Swords Dance and either pass them to a partner with BP, or attempt its own sweep. Mew can do the same thing, except it can Baton Pass defensive boosts which Celebi can't. Deoxys-D can start setting up Cosmic Powers or just throw shit onto the field to support its team through SpikeStacking; dual screens are also an option. Latias can start CMing up or set up stuff like dual screens. Scizor can set up Swords Dance to put some serious pain on the Deoxys's team with Bullet Punch. Kirikizan can start going for the Sub/Swords Dance strategy, which in my vast experience of using it, is extremely deadly.
Even stuff like Venusaur in the Sun, although it has to come in after something has died, can come in and put Deoxys to sleep with Sleep Powder, set up Growth, and wreck the opposing team.
Speaking of coming in after something has died, this is often what Deoxys-N has to do. Therefore, it's a liability to keep switching him out whenever he's threatened, because it's very difficult to actually bring him in without something dying, which is why I say he's difficult to use. If he ends up not doing anything significant when he comes in on that revenge-kill, you basically just sacrificed a team member for nothing.
Another reason why Deoxys-N is hard to use is that he has horrible, horrible 4 moveslot syndrome. He needs his moveset to be Psycho Boost/Psychic/Superpower/Ice Beam/Shadow Ball/Thunderbolt/Hidden Power Fire/ExtremeSpeed. That's 8 moves right there, but he can only carry 4. This means that no matter what, he's going to be screwed by something, which is not very encouraging when you consider that he can't afford to be screwed by something if it's so hard to bring him in.
I personally don't see Deoxys-N ruining any playstyles like Manaphy does. Stall can deal with him because he simply can't deal enough damage to those teams, since like I said, nonSTAB 80-95 BP isn't going to be doing very much damage to a prepared Stall team. Offense can deal with him because they're most likely going to have shit that's faster than him (Choice Scarfers, Chlorophyll/Swift Swim/Sand Thrower). Balanced is a combination, so it can deal with him as well.
People are just intimidated by the high attack stats, but don't seem to realize that BP of attacks matters too, and besides Psycho Boost, which has a horrible side effect and is significantly worse than Draco Meteor, Deoxys-N is lacking in high BP moves.
Just as an example:
Venusaur in the Sun with 252 Atk / 4 SpA / 252 Spe with a Lonely Nature has the following stats with a Life Orb:
301/375/181/306/236/518
Deoxys-N with 4 Atk / 252 SpA / 252 Spe and a Naive nature has the following stats with a Life Orb:
241/438/136/518/122/438
While it may seem as though Deoxys-N would be hitting way harder than this Venusaur, a closer look needs to be taken. Venusaur's main STAB, Power Whip, has 120 BP. Deoxys-N has Psychic, which is 90 BP. According to calculations comparing the actual power behind each attack when you take into account their stats, Deoxys-N's Psychic only has about 3.5% more power, which means that despite the humongous attacking stat, Venusaur's Power Whip is very close in power to Deoxys-N's Psychic. When you also take into account that Venusaur can double both attacking stats with Growth, while Deoxys-N can't practically set up anything without dying, Venusaur's higher BP on its attacks prevails in the end. This is also the reason why damn near any Rain sweeper is more powerful than Deoxys-N; it's the BP.
EDIT: Power Whip and Chlorophyll are apparently illegal together (though not on the ladder IIRC), but my point still stands, because even with Venusaur's modest 82 base Attack, the power of his main STAB is almost identical to the STAB of pokemon with base 150 thanks to the BP. If you want a legal example, look at literally any Swift Swimmer with a reasonable offensive stat in Rain and you'll see that because of the base power of their attacks, they rival, or beat Deoxys-N in power while even being faster. Or if you want another example of a Chlorophyller, substitute Tangrowth for Venusaur, who literally does the exact same thing Venusaur does while only missing Deoxys-N by 2 points of Speed.
That's all I have to say on this matter. I highly recommend bringing down Deoxys-N for testing so he can have a real chance in OU instead of receiving the unfair blanket ban that he got with Deoxys-A.