Great wall of china UU
Steelix (M) @ Air Balloon / Leftovers
Trait: Sturdy
EVs: 252 HP / 252 SDef / 4 Spd
Careful Nature (+SDef, -SAtk)
- Stealth Rock
- Roar / Dragon Tail
- Earthquake
- Ice Fang / Stone Edge / Knock Down
This is pretty much the standard / best way to play a Steelix. The given EVs mean that he can beat defencive zapdos one on one (taking only 46-54% damage thus never 2HKOd whilst holding leftovers) whilst maximising his defencive Potential. With his massive defences he can make for a great Utility Pokémon, packing both Stealth Rocks and a phazing move of his choice.
Given his typing he'll mostly be used to switch in on things like Garchomp, Ice fang is always a 2HKO on non Yache Garchomp, the Air balloon can be used to ensure that Garchomp can't touch him. With an Air balloon he can also make quite an effective Excadrill check, if he switches into an swords dance or protect he can easily Earthquake it to oblivion or Phaze it out, depending on the variant it's up against. Ice fang can be foregone for Stone Edge or knock down to get the every lovely Quake Edge coverage. However, due to his lacking attack, Knock down is recommended so that he can instead nail things with STAB earthquake.
Venomous Snake
Steelix (M) @ Leftovers
Trait: Sturdy
EVs: 252 HP / 252 SDef / 4 Spd
Careful Nature (+SDef, -SAtk)
- Toxic / Body Slam
- Dragon Tail / Roar
- Sleep Talk
- Rest
This Variant of Steelix is made to pass status through the opponent's team and can be really quite effective if used on a stall team that packs a lot of Entry Hazards and needs a Dragon / Status absorber. The idea is simple, bring him in on a Pokemon like Garchomp locked into Outrage, hit it with your status inflicter of choice, rest and then Phaze it out of play. Then rinse and repeat. The EVs here also mean that you can get passed the standard mixed Tyranitar / Specially Defencive Tyranitar one on one so long as it lacks life orb.
The EVs are again used for maximising his defencive potential. The moveset is fairly simple. Rest and Sleep talk are there for Longevity, Toxic is the aim of the set, however body slam can be used to get some occasional Parahax and then the phazing move is down to preference.
Also Rest + sturdy = winrar.
Curse
Steelix (M) @ Leftovers
Trait: Sturdy
EVs: 252 HP / 4 Atk / 252 SDef
Careful Nature (+SDef, -SAtk)
- Curse
- Gyro Ball
- Earthquake / Taunt
- Rest
This set aims to sweep / tank through the opposition via a Curse set. The Evs and Nature maximise his overall bulk. The set is fairly simple, switch in on Chansey / Blissey and start Spamming Curse until you're at a nice and high attacking level. You then rest off the damage and laugh at the pitiful damage being done to you as you rest, you then fire off STABed powered up Gyroballs at will. The next move is down to preference. Earthquake gives you an extra attacking option, whilst taunt stops you being Roared away.
Pre Evo
U mad, Bro?
Onix (M) @ Eviolite
Trait: Sturdy
EVs: 252 Def / 252 SDef / 4 Spd
Careful Nature (+SDef, -SAtk)
- Torment
- Toxic
- Substitute
- Protect
Onix can make a very potent torment user whilst holding the Eviolite item. The set is fairly simple again, switch in on anything that isn't a water / grass / ground type and hit a substitute, then nail the next switch in with a torment as it tries to break your sub, you then hit it with a toxic as it tries to nail you with a coverage move / switches out. Use protect on the next move and switch out to a pokemon that can take the next attack.
The lack of recovery / leftovers is very noticeable so it is best used on a team that has either a wish passer, Leech seed support or Ingrain Passing support... or all three.
LC
Lead Onix
Onix (M) @ Eviolite
Trait: Sturdy
EVs: 196 Def / 236 SDef / 76 Spd
Careful Nature (+SDef, -SAtk)
- Stealth Rock
- Taunt
- Stone Edge
- Roar / Dragon Tail / Earthquake / Explosion / rest
Onix has obscene defences in Little Cup and it also isn't all that slow either. Onix is pretty much the bulkiest lead that you'll find in Little cup and also has speed enough to out pace pokemon that rest on 13 speed or less. This means it can very quickly shut down ferroseed and some other slow utility leads and set up its own rocks. The move of choice here is Stone Edge, as it will hit lead Snove pretty hard and is his most powerful attack. The last option is down to what you want from it. With Roar you can come back later in game and Phaze set up sweepers away. Dragon Tail gets a special mention for being able to deal with Dratini much better, so long as Dratini lacks Surf. Earthquake is cool for coverage, though with Onix's pitiful attack stat, coverage isn't going to help much. Explosion means you can go out with a boom... however this is unadviseable as Explosion got nerfed and Onix won't be hitting very hard with base 45 Attack, anyway. Rest can be used for awesome tanking later in the game... Also Rest + Sturdy is win.
The Torment set from above can also be used here.
U mad, Bro?
Onix (M) @ Eviolite
Trait: Sturdy
EVs: 196 Def / 236 SDef / 76 Spd
Careful Nature (+SDef, -SAtk)
- Torment
- Toxic
- Substitute
- Protect
Partners for Onix
Hippopatas is the best Partner for Onix in LC, as it brings the sands to further bolster Onix's obscene defences. Ferroseed is a great partner, also, as it can destroy bulky waters for Onix and provide it the much needed Leech seed support. Hippopatas / Onix / Ferroseed will be pretty much unstoppable. Just watch out for Choice Scarf Vulpix.
Countering Onix
Totodile gets a special Mention for countering Onix, as it can set up Swords Dance in onix's face and start spamming Aqua jet. Basically any bulky Water / Grass (or not even bulky) will destroy Onix. Tentacool, Belsprout can both get passed the Torment set fairly easily, and can even get passed any other set if they can get passed Earthquake.
Partners for Steelix
Tentacruel
Tentacruel is arguably Steelix's best partner, as between them they can set up 2/3 of the Entry Hazards Required from a stall team. Not only that but Tentacruel removes a pokemon that threaten all Steel Types; Infernape. Aside from the combined ground weakness, they also resist each other's weaknesses quite well and can take hits for the other's weaker stat.
Slowbro
Slowbro is as good as tentacruel in partnership with Steelix, if not better, it just lacks Toxic Spikes Support. Slowbro can come in on any of Steelix's weaknesses very well and Steelix can do the same in return. Slowbro can also remove Ferrothorn, who will be tricky for any stall team to face and Ferrothorn can also set up all over Steelix.
Starmie
For more offencive teams, Starmie makes a great partner for Steelix. With the same typing as slowbro it resists all of Steelix's weak points and also has the added effect of being able to take out infernape like Tentacruel. It can also take out another one of steelix's biggest threat; Gliscor.
Bulky waters in general
Celebi
Though sharing a fire weakness, it can pass Leech Seeds / screens to Steelix to help it tank and also remove bulky waters that threaten Steelix.
Ferrothorn
Again sharing the fire weakness, however it can also pass Seeds to Steelix and set toxic spikes. Steelix / Ferrothorn / Tentacruel could also make a very nice Denfencive core with access to all the entry hazards and Leech Seeds to keep them all nice and lively.
Bulky Grassers In general
Countering Steelix
Heatran
The common Balloon set for Heatran ruins Steelix and can either OHKO it with Fire Blast or Earthpower, or force it out.
Infernape
Infernape can switch in on anything other than Earthquake and harrass it with any of its stab moves
Politoed / Ninetales
Both of them can use Steelix to set up their respected weathers and then OHKO with their weather boosted STAB moves.
Ferrothorn
Ferrothorn can use Steelix as Set up bait and smack away at the behemoth with Power Whips
Breloom
Can use Steelix as Set up bait.
Jellicent
Watching out for the rare Crunch, Jellicent can easily dispose of Steelix and cripple it with recover and Scald, it can also render Steelix pretty useless by Taunting it.
Rotom-W/H
Rotom-W is untouchable at the best of times, however it murders Steelix. Stab Hydro Pump / Stab Over Heat will destroy Steelix. The utility variants of any Rotom can also burn and eventually beat Steelix.
Gliscor
Even the most offencive of Steelix sets can't touch Gliscor, whilst Gliscor can set up on steelix and then proceed to sweep.
Lower Tiers
Moltres
Watching out For Stone Edge / Knock Down, Moltress can switch in pretty easily on Steelix and OHKO with STAB Fire Blast
Milotic
Steelix can't touch milotic, whilst milotic can smack away with it at STAB Scald / Surf and can rest off whatever damage Steelix might Inflict.
Tangrowth
Tangrowth can molest Steelix in any number of ways, be it set up Swords dance and proceed to destroy it, set up leech seeds to slowly conquer the behemoth or set up on it in anyway it wants
TL; DR Fire / Water / Grass Types
Other Options
Choice Band
A choice band set can be formulated to bolster its pitiful attack stat.
Passho / Occa / Shuca Berries
The Weakness berries can be used to help with certain pokemon. Passho means that Steelix might be able to stand a chance against Tentacruel, Occa means it might be able to come out on top over Non-balloon Heatran, and Shuca berry gives you a mistake margin for switching in on Garchomp.
Automize / Rock Polish
Could be useful if you can pass it some attack boosts. If not don't get your hopes up. It's slow as hell and won't be sweeping with unboosted base 80 atk (252/0 Gliscor takes 59% damage max from max Steelix. Not enough to 2HKO after Poison heal recovery)
Crunch
Crunch could be used for a little extra coverage. But Steelix won't be hitting anything hard enough for it to be useful anyway.
Torment
Steelix could run a torment set, however Onix does this better.
Magnet rise
Not a bad option if you don't want to be caught without Leftovers. This means Steelix will beat Excadrill 100% of the time and it gives it a much better chance of beating Gliscor.
Payback
Could be used on the Curse Set, however the lack of coverage with Gyro ball is very noticeable.
Screech
Screech can be used to help Onix get passed Gliscor, however you may as well just be running the curse set.
