Poliwrath Description

Poliwrath, The Tadpole Pokémon. 

With its extremely tough muscles, it can keep swimming in the Pacific Ocean without resting. This strong and skilled swimmer is even capable of crossing the Pacific Ocean just by kicking. Although an energetic, skilled swimmer that uses all of its muscles, it lives on dry land.
Overview

Poliwrath was Water / Fighting before it was cool (looking at you Keldeo, and also I apologize for the overused hipster pun), and is quite a solid Pokemon in the RarelyUsed tier. Having decent offenses and even better defenses, as well as good coverage and a solid typing and ability, Poliwrath is a prominent threat. Although its offensive stats are relatively low, it makes up for it with a good support movepool as well as Bulk Up to help boost its Attack. And despite not being as good as its fellow Water / Fighting Keldeo or its cousin evolution Politoed, Poliwrath can hold its own in the tier it resides in and fill a couple of roles very well.

Abilities
Water Absorb: Heals 1/4 of Poliwrath's max health when hit by a Water move, probably Poliwrath's best ability in RU at least as it allows him to switch in on several threats such as Feraligatr and Kabutops without too much fear.
Damp: Prevents Explosion, Selfdestruct, and the ability Aftermath from doing damage. A very situational ability, and definitely not as good this generation as Explosion is significantly worse.
Swift Swim: Doubles Poliwrath's Speed when Rain is present, a good ability and makes up for Poliwrath's lack of Speed, although there are not too many Rain setters in RU and there are better sweepers to abuse said Rain with.
Movesets
The Poliwrath of Khan
-Circle Throw
-Scald / Toxic
-Rest
-Sleep Talk
Item Attached: Leftovers
Ability: Water Absorb
EVs and Nature:
EVs: 252 HP / 252 Def / 4 SDef
Relaxed Nature (+Def, -Spe)
This is the standard supporting set for Poliwrath, and it functions as a good phazer in RU. Circle Throw does solid damage (thanks to the STAB boost) as well as phazes out the opponent, which combined with a hazards setter can be quite damaging to the opponent's team. Scald and Toxic are the option for the second slot, as both provide some sort of status condition, although Scald is often better as it provides damage as well as burning many annoying opponents. Toxic is more useful in the realm of helping to take down opposing Pokemon that are bulkier. Rest is a reliable source of recovery, although not too good as it puts you to Sleep, though Rest allows Poliwrath to be a sponge for different statuses as it can just Rest them away when they become irritating. Sleep Talk remedies the sleeping problem somewhat as it allows Poliwrath to still attack despite being asleep, although it may not use what you want it to.
Grapes of Poliwrath
-Substitute
-Bulk Up / Encore
-Waterfall
-Focus Punch
Item Attached: Leftovers
Ability: Water Absorb
EVs and Nature:
EVs: 160 HP / 252 Atk / 96 Spe
Adamant Nature (+Atk, -SAtk)
This set, although a little more obscure than the other set, is still one of the more popular sets to run on Poliwrath. Substitute provides protection from status, damage, etc. which can be very useful when facing a more bulky foe that relies on those to wear you down, as well as giving you an opportunity (if the Substitute isn't destroyed) to either Bulk Up or Encore the opponent. Bulk Up is a good boosting move that raises both Attack and Defense, very helpful as it raises Poliwrath's decent Attack and Defense stats even higher, both making Poliwrath a more offensive powerhouse and also a bulkier wall at the same time. Encore on the other hand allows you to either force a switch by locking an opponent into an undesirable move, or lock them into an attacking move that another Pokemon can handle. Waterfall is reliable STAB that does quite a bit of damage, especially with some Attack boosts behind it. Focus Punch is somewhat less reliable as it requires you to have a Substitute up to really be guaranteed to work, but if you have one up, Focus Punch can do considerable damage to even the Pokemon that resist it. The EV spread allows you to outspeed several threats such as Aggron, while still allowing for bulk and high attack.
Other Options
Belly Drum, Body Slam, Earthquake, Ice Punch, Low Sweep, Payback, Rain Dance, Rock Slide, Work Up
Belly Drum halves Poliwrath's HP but boosts its Attack to maximum. Poliwrath can use this pretty well, although the HP drop can often lead to it being KO'd before it gets a chance to attack.
Body Slam does decent damage as well as having a chance for paralysis, a good filler move for Poliwrath but STAB moves or better coverage moves are the wiser choice.
Earthquake is a good coverage move and does considerable damage, but doesn't really hit too much that any of Poliwrath's Fighting moves doesn't already.
Ice Punch is a good coverage move as well as it can hit Flying and Dragon types for solid damage.
Low Sweep is an alternative Fighting STAB, and although a bit weak, it does provide a Speed drop when it hits.
Payback can be very useful on Poliwrath, hitting bulkier Ghost and Psychic types for high damage, especially if they hit Poliwrath prior to the attack.
Rain Dance is very useful for a Swift Swim team or even just a Swift Swim Poliwrath as it can provide its own massive Speed boost.
Rock Slide, like Ice Punch, hits Flying types decently, although its shaky accuracy is a little undesirable.
Work Up provides boosts for both Attack and Special Attack, making a mixed Poliwrath set somewhat viable (not too much really, but hey, it could work if you're lucky enough).
Double & Triple Battle Options
Poliwrath is used completely differently from Singles in Doubles and Triples, as it generally runs Swift Swim on more offensive sets (since Rain is common), as well as running some of our other options, in addition to some other moves, including Belly Drum, Icy Wind, Brick Break, Protect, Helping Hand, and so on.
Partners
Good partners for Poliwrath are hazard setters (for the Circle Throw set at least), as they can set up either Stealth Rock or Spikes, and then Poliwrath can proceed to switch them out so that they keep taking damage. Partners that can deal with Grass, Electric, Flying, and Psychic types are also very valuable to Poliwrath as they help it to avoid its weaknesses
Countering Poliwrath
Tangrowth is the best counter in RU to Poliwrath as it resists one of its STABs, is very defensively bulky, and deals super effective damage to Poliwrath with its own STAB. Rotom-C, Sceptile, and Lilligant are also other pretty common Grass types that can generally KO Poliwrath, but they have to be wary of more physical sets as they could end up getting KO'd switching in. Ghosts such as Dusknoir, Spiritomb, and Rotom all fall into this boat as well, although worrying about the other STAB. Bulkier Waters and Psychics also do well against Poliwrath, and can either status it or KO it, with Pokemon like Qwilfish, Uxie, Slowking, and others all can take minimal damage and do plenty in return via Toxic or an attacking move.

Pre-Evolution Corner - Poliwag (Little Cup)
Yes, that pink thing is actually my mouth
-Hydro Pump / Surf / Scald
-Ice Beam / Blizzard
-Hidden Power (Grass) / Hidden Power (Fire)
-Hypnosis / Rain Dance / Substitute
Item Attached: Life Orb / Eviolite
Ability: Water Absorb / Swift Swim
EVs and Nature:
EVs: 36 Def / 200 SAtk / 36 SDef/ 196 Spe
Timid Nature (+Spe, - Atk)
Poliwag has a lot of things going for it for just a tadpole. A decently large movepool, max of 19 speed, access to Swift Swim, at the cost of being very frail, and not having super high attacking stats. Hydro Pump is an excellent STAB move that hits very hard. If you want more accuracy though, Surf is a fine replacement and Scald helps with physical attackers. Ice Beam is very helpful for clearing out bulky Grass-Types like Foongus and Lileep. Blizzard is a better alternative if you have hail support from Snover. Hidden Power Grass helps to deal with bulky Water-Types like Frillish and Staryu. Hidden Power Fire is reserved for Ferroseed, or Steel-Types if you want to run a weaker option for your Water STAB. Hypnosis is great to put threats out of business for a few turns and get good hits in. Rain Dance powers up your Water moves, and doubles Poliwag's speed from 19 to 38. Substitute is also a viable option to protect your frailness for one turn or to block out Thunder Waves or other status effects. Life Orb helps Poliwag do actual damage, since it’s base Special Attack is low. Eviolite helps with Poliwag’s bulk problem a bit. The EV’s and nature capitalize Poliwag’s speed and Special Attack, whilst dumping the other points into it’s non-existent bulk. For other sets, you could a decently useful scarf set, but Poliwag lacks damage without Life Orb. A Belly Drum set could also work, but it takes away from Poliwag more versatile special moves, and is even easier to revenge kill with priority or Choice Scarf. Poliwag isn't necessarily hard to check Poliwag as well. Due to it’s lack of bulk, its easy to dominate it with faster speeds, priority, or just being bulky enough to take a hit. Even with these problems, Poliwag is surprisingly useful.

Locations in Games
Ruby/Sapphire/Emerald:
Trade from FireRed/LeafGreen
FireRed/LeafGreen:
Evolve Poliwhirl
Colosseum/XD:
Trade from FireRed/LeafGreen (Colosseum)
Snagged from Cipher Admin Gorigan in Citadark Isle (XD)
Diamond/Pearl/Platinum:
Evolve Poliwhirl
HeartGold/SoulSilver:
Evolve Poliwhirl
Black/White:
Wellspring Cave, Challenger's Cave, Victory Road, Giant Chasm
Black 2/White 2:
Route 23, Relic Passage, Wellspring Cave, Clay Tunnel, Giant Chasm, Victory Road