Slowbro: Champion of the People
Time for a LONG post on why Slowbro is a champ and should be used whenever possible.
Between its typing, bulk, and ability, Slowbro is extremely robust against several common, dangerous Pokemon in the tier while also being a decent half-measure against even more.
Its typing offers key resistances to the following types: Water, Fighting, Ice, Psychic, Fire, and Steel. It is also not weak to Rock, Ground, or Dragon, letting it check a lot of physical attackers in the tier even if it can't wall them forever.
Its match-up against the ice types is the easiest niche to carve for it, but naturally, Slowbro needs some specific support in the builder to truly shine.
It's grounded, so it's therefore spikes-weak. This means it mandates Drill support, but this is hardly a flaw worth criticizing.
It strongly dislikes status: if it gets burned or poisoned, it can eventually get overwhelmed by the opponent having multiple Pokemon Slowbro's trying to check. A status absorber like Celebi or Poison Heal Breloom could be a good partner as a result. That being said, something like Mamo is hard-pressed to break through bro by itself even if it takes a burn, so it ultimately depends on what Slowbro's needed for in a given game.
Pokemon Slowbro Blanks:
The Ice resistance ends up being the reason Slowbro is arguably the hardest counter to Mamoswine in the game: the hardest hit Mamoswine could possibly muster on it would be CB EQ, which Slowbro easily pivots into:
252+ Atk Choice Band Mamoswine Earthquake vs. 248 HP / 252+ Def Slowbro: 181-214 (46 - 54.4%) -- guaranteed 2HKO after Stealth Rock
Thanks to Regenerator, Slowbro can heal off some of the damage and swap into a ground immune now that they've revealed CB. Considering this was the damage Mamo did while banded, forget about getting Mamo to ever break a healthy Slowbro.
Furthermore, Slowbro also hard-counters Cloyster.
+2 252+ Atk Life Orb Cloyster Rock Blast (5 hits) vs. 248 HP / 252+ Def Slowbro: 220-260 (55.9 - 66.1%) -- approx. 2HKO after Stealth Rock
This is with Life Orb, and Slowbro could easily take it even if Cloy crits 1-2 of the hits.
Slowbro, of course, is also excellent against several Pokemon that aren't Mamo/Cloy.
It's a Fighting resist with massive physical bulk and Regenerator, making it arguably the hardest counter in the game to Terrakion as well.
252 Atk Choice Band Terrakion X-Scissor vs. 248 HP / 252+ Def Slowbro: 176-208 (44.7 - 52.9%) -- guaranteed 2HKO after Stealth Rock
252 Atk Choice Band Terrakion Stone Edge vs. 248 HP / 252+ Def Slowbro: 165-195 (41.9 - 49.6%) -- 86.7% chance to 2HKO after Stealth Rock
252 Atk Choice Band Terrakion Close Combat vs. 248 HP / 252+ Def Slowbro: 99-117 (25.1 - 29.7%) -- 1.1% chance to 3HKO after Stealth Rock
Just like with CB Mamo, if Terrak locks Stone Edge/X-Scissor, that's easy to pivot out of while healing off some of the damage with Regen.
For reference, it takes less damage than even the standard fast Landorus-T while also being harder to wear down if spikes are kept off the field (Spikes + Terrak is on the rarer side as well).
-1 252 Atk Choice Band Terrakion Stone Edge vs. 240 HP / 16 Def Landorus-Therian: 175-207 (46.1 - 54.6%) -- 98.4% chance to 2HKO after Stealth Rock and Leftovers recovery
Pokemon Slowbro Checks:
Slowbro forever walls the Ices and Terrak, but it's a blanket check to most physical attackers, e.g. the physical dragons beyond Kyurem-Black.
+1 252+ Atk Dragonite Outrage vs. 248 HP / 252+ Def Slowbro: 222-262 (56.4 - 66.6%) -- guaranteed 2HKO after Stealth Rock
+2 252+ Atk Dragonite Outrage vs. 248 HP / 252+ Def Slowbro: 297-351 (75.5 - 89.3%) -- 12.5% chance to OHKO after Stealth Rock
+2 252 Atk Garchomp Outrage vs. 248 HP / 252+ Def Slowbro: 264-312 (67.1 - 79.3%) -- guaranteed 2HKO after Stealth Rock
+2 252+ Atk Garchomp Outrage vs. 248 HP / 252+ Def Slowbro: 289-342 (73.5 - 87%) -- guaranteed 2HKO after Stealth Rock
0 SpA Slowbro Ice Beam vs. 0 HP / 0 SpD Garchomp: 316-372 (88.5 - 104.2%) -- 62.5% chance to OHKO after Stealth Rock
0 SpA Slowbro Ice Beam vs. 0 HP / 4 SpD Dragonite: 272-324 (84.2 - 100.3%) -- guaranteed OHKO after Stealth Rock
This is one reason I really like Rocky Helmet on Slowbro: if they smack you with their boosted Outrage, you can KO them in return if they don't have Yache berries. If Slowbro's facing down a Scarf Chomp instead of SD or a Scarf Mence, they can forget about ever breaking it.
Slowbro's also great against Grounds.
0 Atk Landorus-Therian Earthquake vs. 248 HP / 252+ Def Slowbro: 102-120 (25.9 - 30.5%) -- 9.7% chance to 3HKO after Stealth Rock
If Slowbro has Rocky Helmet, it can punish Lando for electing to use U-turn, and it can still escape from ttar if need be as long as it swaps into the U-turn still healthy:
88+ Atk Tyranitar switching boosted Pursuit (80 BP) vs. 248 HP / 252+ Def Slowbro: 176-210 (44.7 - 53.4%) -- guaranteed 2HKO after Stealth Rock and sandstorm damage
252+ Atk Sand Force Excadrill Earthquake vs. 248 HP / 252+ Def Slowbro in Sand: 162-192 (41.2 - 48.8%) -- guaranteed 2HKO after Stealth Rock and sandstorm damage
This is the strongest possible drill, and it barely 2HKOs slowbro in Sand with SR up. The fact that it will munch Iron Head means that Slowbro can start some mind-games with Drill in terms of whether it wants to use Iron Head to catch Lando (or another ground immune) or to EQ to catch Slowbro. This is especially helpful when using a more offensive Lando that doesn't take hits from drill as easily.
Pokemon Slowbro is like a quarter-to-half-measure to:
While Slowbro is not robust against special attacks with the max/max Bold spread I've been citing for calcs, its typing lets it serve as a half-measure against Keldeo and potentially Alakazam.
252 SpA Keldeo Surf vs. 248 HP / 8 SpD Slowbro in Rain: 138-162 (35.1 - 41.2%) -- guaranteed 3HKO after Stealth Rock
Slowbro can comfortably switch into an unrevealed Keldeo. If they reveal Specs or Ebelt Hidden Power Grass/Ghost/Bug, then Slowbro's can't really answer it with this spread, but it can help against Scarf and other sets that lack Toxic or HP Grass/Ghost/Bug (which I think are bad but that's neither here nor there). With a Psychic move, Slowbro can even answer Sub Keldeo (and Psychic has the benefit of breaking Subs on mons like Tentacruel and Gyarados in addition to whacking various Fighting types, including more niche ones like Conkeldurr or Toxicroak, and OHKOing Cloyster).
If running Thunder Wave, Slowbro can even attempt to cripple Alakazam.
252 SpA Alakazam Grass Knot (80 BP) vs. 248 HP / 8 SpD Slowbro: 214-254 (54.4 - 64.6%) -- guaranteed 2HKO after Stealth Rock
This is the strongest hit Zam can muster, and Slowbro easily takes it if spikes are kept off the field. Furthermore, Psy/Ice/Focus + Twave/Encore is totally a thing, so Zam carrying a move for bro isn't a given necessarily, even if it's the most common scenario.
Benefits of Incorporating Slowbro and Possible Teambuilding Routes:
As alluded to earlier, Slowbro can enable more offensive lando sets thanks to its ability to take on opposing Grounds and Terrak. It's even a good partner for Gravity Lando since it can soak up opposing EQs pretty easily. It also opens the possibility of forgoing Lando and using Garchomp on Sand, with the remaining four being picked accordingly naturally.
One of the team structures I've thought Slowbro shines is a 5-mon start with a fairly flexible 6th slot: Chople tar/ScarfChomp/Specs Latios/Slowbro/SD Spin Drill. The 6th slot wants to address some of the following: Tech Loom, Sciz, Spikers, Rotom. My favorite 6th is probably Zapdos, but Thundurus works similarly and is better against rotom/gastro/ttar/opposing thund in exchange for worse bulk and no roost. Latias is also a possibility (probably mandates Flamethrower on Slowbro to scare Ferro/beat Sciz in a pinch). Pheal Loom or Hydreigon can work too, but those are pretty greedy options that make you a lot weaker to Skarm and Tech Loom, respectively, but they have their upsides nonetheless.
There's other options too, but the slight annoyance with Slowbro is that it's going to be mutually exclusive with Rotom, and it's also not good enough against Keld stand-alone generally (Celebi/Latios is a likely pairing as a result). It's a good idea to view how to pick one's water resists from the lens of beating Starmie and Keldeo, and unlike Rotom, Slowbro is not very good against Starmie, so Slowbro teams will occasionally feel a little soft against Starmie. It's definitely not to an unmanageable extent, though. Furthermore, not having Rotom also means losing out on Volt Switch and its obvious benefits, but considering Slowbro's many positive traits, this is hardly to say that Slowbro is hard to justify.
> 
Excadrill @ Leftovers
Thundurus-T@Leftovers
Bronzong @ Macho Brace
Donphan @ Leftovers
Tyranitar @ Choice Scarf
@ Soft Sand / Earth Plate
The Cavern Menace: A Terrakion Retrospective 
The Sleep Ban and PHeal Loom Sand Era 
Celebi Sand Balance Era 
Gems Era and Rak's Decline 
