I am usually not a player of Ubers. I always kept myself out of it knowing I'd be terrible at it. It was about two months ago when I finally decided to hit the 'Look for a Battle' button in Ubers, and I don't regret it.
This is my first Ubers team, and is still probably one of my most successful teams. It has taken work and time, but it has climbed to 1782 on the ladder, and is almost ready to go into the top 500 on Showdown!.
The team itself was made around Lugia, one of my favourite legendary Pokemon from the old games and an insanely great wall and Toxic staller if you can use it well. It has 106 / 130 / 154 base Defences and a legendary ability in Multiscale, which makes it an amazing switch-in and a better option than Giratina-A who sports a Dragon weakness, leaving it prone to CB Zekrom's Outrage and other powerful Dragon attacks in the tier.
The team is not perfect of course, and I'd appreciate it if somebody could correct any problems they see with the team. The main thing I see is that it is incredibly unoriginal, as it contains a Pokemon that over 40% of teams use and a Pokemon that is used for priority sweeps, so that is one thing I'd like to fix.
Enough of that though. Lets begin. Please prepare for a giant wall of text. :D
Process & the team
The team started off with Lugia, an amazing wall that I wanted to use. This thing will gladly switch in on the most powerful attacks, such a Kyurem-W's Draco Meteor thanks to Multiscale, which helps it set a Substitute and Roost off damage while watching the opponent die a long and frustrating death from poisoning.
The next Pokemon I added was a hazard setter. If I remember correctly, this teamslot was once occupied by Counter Forretress (I will remind you of how amazing that thing is), however after playing a few battles, I realised that Ubers is a little too overwhelming for a little bug like him, so I swapped him for a classic wall that can function properly in both OU and Ubers - Ferrothorn. This thing provides Lugia with with key resistances to Arceus-Ghost's Judgement / Shadow Claw and Darkrai's Dark Pulse. It also assists the team with Spikes and Leech Seed that slowly absorb HP, and can help with the many OHKOs the team aims to get.
Clearly the team lacks an attacking Pokemon. And one of Ferothorn's biggest flaws is it's horrifying 4x Fire weakness to Rayquaza's V-create, Kyurem-W and Reshiram's Fusion Flare, et cetera et cetera. The easiest way to remove this crippling weakness is to add a Water type. And who is better for the job than Kyorge? This big fish will lands countless OHKOs on many threatening Pokemon like Genesect and non-Sash Darkrai, and provides rain support to lower Ferro's Fire weakness and overwhelm the tier with Water Spout. The main issue with Kyogre is its disappointing 90 Speed. So I added a Scarf to outspeed other Kyorge and kill them with Thunder or revenge kill things with Water Spout.
At this point, I wanted to add a physical attacker, simply because the pink eggs wall me and if Lugia went down I'd be in trouble. However, before I added a Pokemon that could fill such a role, I needed a status absorber that, with prediction, could save Kyogre from Dark Void or Ferrothorn from Thunder Wave. Since I had rain support, I thought, "why not try Manaphy?" This little fairy has an amazing ability Hydration, which heals it from all status problems that come its way, if it is raining. This little guy proves to be an excellent counter to Darkrai, Giratina-A, Lugia and defensive Dialga, who often run away giving me a free Tail Glow. Some people are also dumb and think I'm using a Lum Berry, and they even attempt to status me again. Great troll, great attacker who will flatten unprepared teams.
The next Pokemon I wanted to add was a beast. With a maximum of 438 Attack unboosted, Choice Band and decent bulk, this Pokemon immediately stood out as a great attacker. This Pokemon was Zekrom, the team's premier wallbreaker who sports a 4x resistance to electricity, which is vital when Thunder has infinite accuracy and three of your team members are weak to it. This makes it a good switch in on things like Specs/Scarf Kyogre locked into Thunder trying to get a kill on one of my Pokemon. Nothing likes an unresisted Outrage to the face.
The next Pokemon I added was Deoxys-Speed, who I wanted for fast Taunt support and a way to get more hazards up. However, it simply wasn't working well and was not a help to the team in terms of synergy. So I wanted a Pokemon that firstly could stop Arceus-Ghost from flattening Lugia and a Pokemon that wouldn't have an effect on my synergy at all. And the Pokemon that stood out here was Arceus, who is weak to just Fighting which is an uncommon type in Ubers apart from Focus Miss and Aura Sphere, which Lugia walls completely. It is easy to set a Swords Dance with Arceus' good bulk, and proceed to kill the opponents team with ExtremeSpeed. He is not walled by Ghosts though; he has Shadow Claw and Brick Break which provide it with good coverage. He will sweep teams easily late-game, and is a thread you should be prepared for, although it is very mainstream.
The team - a closer look
The character limit has screwed me, so the team is in the below answer. Everything together comes to roughly 9,500 characters.
I congratulate you if you've read everything so far.