I'm bored at work so I'm gonna go through this and try
to update it. ^.^
All this is for the Offensive section.
Druddigon (Choice Band / LO set) and Emboar (Choice Band / Scarf) would like a mention.
Druddigon makes everything cry with its Choice Banded Outrage, and LO causes a similar level of damage.
Emboar doesn't have a SR weakness and has a Fighting-type STAB. Wild Charge is available to hit Water-types. Head Smash is really k00l.
Entei, Electivire don't need an update.
Feraligatr: Removed mention of Cofagrigus, and added a bit about other Pokemon that can stop it
Should Fraxure get an entry? I feel as it should, but QC has the say.
Fraxure is one of the few Dragon-types and one of the better ones (sorry Gabite and Altaria). Evolite means it has decent bulk, and DD / SD means that it can easily take everything down. The lack of Steel-types means that Substitute / Taunt can be used.
Gallade doesn't need an update
Galvantula: Added more emphasise for HP Ground, mentioned Volt Switch, and SR weakness
Typing: Bug / Electric
Base Stats: 70 HP / 77 Atk / 60 Def / 97 SpA / 60 SpD / 108 Spe
Abilities: Compoundeyes / Unnerve / Swarm
Although most players choose Rotom or Manectric as their offensive Electric-type, Galvantula should not be overlooked. Thanks to Compoundeyes, it can make use of a 91% accurate Thunder, hitting much harder than Rotom's Thunderbolt. It also has excellent coverage moves, with STAB Bug Buzz, Energy Ball, and Hidden Power Ground to choose from. Combined with a base 108 Speed stat, Galvantula is one of the most threatening all-out sweepers in the tier. Galvantula is also an excellent scout with a speedy Volt Switch. However, it is very frail, so the few things that do outspeed it, mostly Choice Scarf and weather-boosted Pokémon, will probably be able to OHKO it. Its Bug typing makes the spider weak to Stealth Rock, which helps to its downfall. Although it isn't the most common threat, you should always prepare for Galvantula because it can blast through slower teams.
Golurk and Gorebyss don't need an update.
Add Hariyama or Haunter to the list?
Hariyama's entry could include: its Guts set with Toxic / Flame Orb combined with a high base 120 Attack. Bulk Up does somewhat work as does SubPunch, but the Status Orb set is the best offensive one.
Haunter is a great offensive spinblocker that's fast (unlike Golurk). It can cause general mayhem with Substitute + 3 Attacks set, or take a page out of Gengar's book and use Substitute + Disable.
Hitmonchan / Lee: Remove Rapid Spin mention? They aren't very good at it, but they do
Jynx: She hasn't changed. Mention the 'Luna' set?
Typing: Rock / Water
Base Stats: 60 HP / 115 Atk / 105 Def / 65 SpA / 70 SpD / 80 Spe
Abilities: Swift Swim / Battle Armor / Weak Armor
Kabutops has most of the perfect tools to be a great sweeper: high Attack backed by Swords Dance, a great dual STAB combination, and priority. Its typing is especially nice, 4x resisting Fire-type attacks, in a tier where Entei has the ultimate firepower. Kabutops can hit almost every Pokémon in the tier at least neutrally, and after a Swords Dance, nothing will enjoy switching into it; furthermore, it has high enough Defense that it can take a hit if needed. Aqua Jet takes on Choice Scarf users such as Typhlosion and Rotom, stopping their revenge killing efforts. Kabutops's low Speed can even be moderately fixed with Swift Swim and rain or Weak Armor, which lowers Defense and raises Speed by one stage when hit with an attack. Kabutops can also take on a supportive role, setting Stealth Rock when forcing a switch and using Rapid Spin to support the number of hazard-weak Pokémon that reside in RU. Such variants are no slouches offensively either, hitting opponents with Waterfall or Stone Edge. Luckily, Kabutop suffers from low Speed, meaning bulky or healthy revenge killers can defeat it rather easily. Furthermore, its typing leaves it weak to Fighting- and Ground-type moves, two attack types that are always around. The bottom line is this: most teams are already prepared for Kabutops when preparing for other threats, but a properly supported shellfish can tear teams apart.
Add Kangaskhan? The Scrappy + Choice Banded Double Edge hurts yo. Also her good 105 / 80 / 80 bulk means she can take some hits. A base 90 Speed also means that she can get the jump on many prominent threats.
Klinklang and Lanturn don't need an update.
Base Stats: 60 HP / 100 Atk / 115 Def / 70 SpA / 85 SpD / 90 Spe
Abilities: Plus / Minus / Clear Body
Klinklang is one of the best offensive Steel-types in RU. It gets an excellent boosting move in Shift Gear, and its signature move Gear Grind allows it to bypass Substitutes, with decent Base Power to boot. After a Shift Gear, it can outspeed all of the metagame, and also becomes very powerful. It usually runs Return as a coverage move due to its awful movepool, and in the fourth slot a number of different moves are commonly seen. Substitute is the most prominent, avoiding status as well as protecting itself from priority. However, it can also run Hidden Power Fire to defeat Ferroseed, or use Hidden Power Ground to escape the clutches of Magneton; both are would-be counters. Straight-up countering Klinklang is pretty difficult, as its Speed and power are unmatched. However, Sandslash is as close as they come, not being 2HKOed by any move from Klinklang even at +1, and can 2HKO back with its STAB Earthquake. Steelix is in a similar position, and can also phaze Klinklang's boosts with Roar. As mentioned before, Ferroseed and Magneton can defeat versions of Klinklang that lack Hidden Power Fire and Hidden Power Ground, respectively. Feraligatr, Entei, and Moltres all resist Gear Grind and are bulky enough to take a +1 Return, and can deal heavy damage with their STAB moves. Also, Hitmonchan can 2HKO Klinklang with Life Orb Mach Punch, although it can't take a boosted attack. All in all, the best way to deal with Klinklang is to prevent it from setting up, as it much more manageable before a Shift Gear than after.
Lilligant: Included HP Fire / Rock
Base Stats: 70 HP / 60 Atk / 75 Def / 110 SpA / 75 SpD / 90 Spe
Abilities: Chlorophyll / Own Tempo / Leaf Guard
Like many other Grass-types, Lilligant has very balanced stats and a very shallow movepool, not to mention Grass is not a great type to begin with. However, Lilligant was blessed with every special attacker's dream: Quiver Dance. Quiver Dance turns Lilligant from a less-than-average sweeper to a very potent one. On top of this, Lilligant couldn't have asked for two better abilities. Chlorophyll doubles its Speed under sun, making Lilligant a strong addition to a Sunny Day team. Own Tempo allows Lilligant to use Petal Dance, as it nullifies the move's confusion, making it a 120 Base Power STAB move with perfect accuracy and no downside, apart from being locked into it for 2-3 turns. Lilligant also has many support options, including Aromatherapy and Sleep Powder. One must be careful when using Lilligant though, as there are many powerful Bug- and Flying-types in RU that Lilligant struggles against, due to its lacking movepool. Hidden Power helps with this though, as Hidden Power Rock hits Fire-types while Hidden Power Fire hits opposing Grass-types. Underestimate Lilligant's power and you will surely pay for it.
Linoone, Ludicolo, Magmortar, Magneton, and Medicham don't need an update.
Mesprit: Mention how it can be a weather supporter? It doesn't directly correlate to offensive threat, but its there
Moltres, Ninjask, and Primeape don't need an update.
Pinsir is great as it can boost with SD and bring it to town with STAB, coverage, and / or Quick Attack; Moxie is k00l too. Honko's RMT is a good example of its power.
Rhydon and Rotom don't need an update.
Rotom-C: Can set up Rain Dance for the team and itself and use Thunder.
Include Rotom-F? Add this entry if Hail is kept in the tier, but no point of Hail's gone.
Samurott, Sandslash, Sawsbuck, Sceptile, Scyther, and Sigilyph don't need an update.
Include Seismitoad? Its hits pretty hard in Rain, but otherwise it doesn't have much utility.
Include Slowking? Choice Specs + Regenerator is great. OTR is a great asset to TR teams. Nasty Plot hits really hard, and all have Slack Off. Really Slow and typing doesn't help it.
Include Skuntank? Its a great trapper, although largely outclassed by Drapion, but has Aftermath and the ability to go mixed with Fire Blast.
Include Sneasal? Speedy little attacker that is also a powerful trapper and priority also helps it. Paper thin defenses don't help it, though.
Include Spiritomb? Choice Banded Spiritomb gained a lot of popularity, and CroTomb is awesome-sauce.
Swellow doesn't need an update.
Include Tangrowth? That great Special Attack and Defense gives the thing a lot of opportunities to switch in, and the looming threat of Sleep Powder keeps checks away. Leaf Storm, Hidden Power Fire / Rock, Focus Blast. Bad Speed and poor Special Defense.
Tauros and Typhlosion don't need an update.
Include Ursaring? The combination of Quick Feet, Toxic Orb, and SD means its a fast bear, and it'll hit really hard with a boosted Facade. Slow prior to setup and can be worn down quickly.
Include Uxie? The SubCM set is gaining popularity, and with that great bulk, oh lala. The massive support movepool means that it can help the team greatly. Is weak without setup, and Dark / Bug-types can still ruin the party.
Zangoose doesn't need an update.
And remove Dusion and Zweilous per Honko's post.
Let's get this list up to date!