After playing some more, I've found the following Pokemon to be really good:
Raichu
That +10 base Speed buff is too important for Raichu in the current NU metagame. With 110 base speed, it outspeeds Durant, on of the most important, if not the most important threat in the metagame so far, speed ties with Archeops and Tauros, and outspeeds stuff like Virizion, Scyther (non-Scarf), Fearow, Dodrio, Rapidash, Pyroar and more. Choice Specs and Life Orb seem to be its best sets, though Life Orb has worked the best for me.
Raichu @ Life Orb
Ability: Lightningrod
EVs: 252 SAtk / 252 Spd / 4 Atk
Hasty Nature
- Knock Off
- Grass Knot
- Volt Switch
- Focus Blast
Raichu provides great momentum for teams with its high speed Volt Switches and cripples opposing Pokemon with Knock Off on the Life Orb set. Grass Knot and Focus Blast screw over most Ground type switch-ins, leaving Raichu with only a handful of counters (Sceptile, Serperior, Scarf Typhlosion...). This (
http://replay.pokemonshowdown.com/nubeta-119402019) replay shows some of Raichu's utility in battle, even if it only appears a few times.
Samurott
Samurott is probably one of the best wallbreakers in the tier. It is amazing what Knock Off can do to some Pokemon. With no Megas in the tier and a lot of Eviolite users, nothing other than perhaps Virizion wants to take a Knock Off in the tier or take a powerful Hydro Pump or Megahorn. Just about every Pokemon should be terrified when Samurott comes out against a slower Pokemon. Whether a Swords Dance sweeper, a mixed Life Orb wallbreaker (<-- Best set here), a Choice Band user, Specs user or Scarf user, Samurott will always be one of the most threatening Pokemon in NU.
Samurott @ Life Orb
Ability: Torrent
EVs: 252 Atk / 4 SAtk / 252 Spd
Naughty/Rash Nature
- Hydro Pump
- Aqua Jet/Ice Beam/Grass Knot
- Knock Off
- Megahorn/Ice Beam/Grass Knot
Unless it carries Swords Dance or a Choice Band/Specs, going mixed is necessary in order for Samurott to be the best wallbreaker it can be, as Knock Off and Hydro Pump are pretty mandatory. Aqua Jet is useful as a last resort move against faster threats and helps to prevent things like Archeops from revenge killing, but is not completely necessary and can be replaced with a better coverage move like Ice Beam, Grass Knot or Megahorn.
Finally there are two Rock types that I'd like to mention that have been very underrated.
Rampardos and
Aurorus
These two are very threatening under a Rock Polish, though are hampered by their many weaknesses and fraility (the latter not so much for Aurorus, but its many weaknesses make it somewhat frail). Rampardos is just crazy strong and has great EdgeQuake coverage with Mold Breaker. NU is much kinder to it than other tiers, allowing it to survive enough hits to Rock Polish and sweep especially with Mach Punch and Bullet Punch being uncommon.
Rampardos @ Life Orb
Ability: Mold Breaker
EVs: 252 Atk / 252 Spd / 4 HP
Adamant/Jolly Nature
- Rock Polish
- Stone Edge
- Earthquake
- Fire Punch/Crunch
After a Rock Polish, Rampardos outspeeds the fastest Pokemon in the tier, Accelgor, (it needs to have at least 214 speed) minus some Scarfers. Ramp can afford to run Jolly though with its Gargantuan power. Not much to say here.
Aurorus is the bigger surprise here, but it can use its weaknesses and solid defensive stats to its advantage using a Weakness Policy set.
Aurorus @ Weakness Policy
Ability: Refrigerate
EVs: 188 SAtk / 252 Spd / 68 HP
Modest Nature
- Rock Polish
- Nature Power
- Discharge
- Earthquake/Ancientpower
I unfortunately don't have a good replay of this guy in action, but it truly does a good job of sweeping. Nature Power Tri Attack is extremely strong, even without the help of Weakness Policy. It gets nice Boltbeam coverage, which is not as effective in NU with Magneton and Lanturn so prevalent in the tier, but they are hit hard with an Earthquake, even with a Modest nature at +2. Just a disclaimer here: DO NOT ATTEMPT TO GET HIT BY FIGHTING ATTACKS, STEEL ATTACKS OR STRONG SE STAB ATTACKS. You should be getting hit by things like weaker Earthquakes, Scalds, Giga Drains, Rock Slides and stuff. I've also used bulky Barrier Weakness Policy sets that worked somewhat well, but were less consistent, so Rock Polish is Aurorus's best bet.