I've been using a mono-fighting team on the ladder competitively (which is easily the best mono team team in my opinion). I've tried Steel, its horribly overrated. See the thing with mono teams is that it is more important than your regular team to work together as a single unit and have a plan. Then you must also cover your ass!!! Here is what I came up with:
Infernape (M) @ Focus Sash
Ability: Blaze
EVs: 252 Spd/252 SAtk/4 SDef
Timid nature (+Spd, -Atk)
- Fire Blast
- Endeavor
- Vacuum Wave
- Stealth Rock
---
Breloom (M) @ Toxic Orb
Ability: Poison Heal
EVs: 240 HP/16 Atk/220 Def/32 Spd
Adamant nature (+Atk, -SAtk)
- Spore
- Stun Spore
- Substitute
- Focus Punch
---
Machamp (M) @ Leftovers
Ability: No Guard
EVs: 252 HP/104 Atk/152 Spd
Adamant nature (+Atk, -SAtk)
- Dynamicpunch
- Ice Punch
- Payback
- Bulk Up
---
Hitmontop (M) @ Life Orb
Ability: Technician
EVs: 232 HP/244 Atk/32 Spd
Adamant nature (+Atk, -SAtk)
- Fake Out
- Close Combat
- Stone Edge
- Mach Punch
---
Lucario (M) @ Life Orb
Ability: Inner Focus
EVs: 252 Atk/252 Spd/4 SDef
Adamant nature (+Atk, -SAtk)
- Close Combat
- Crunch
- Extremespeed
- Swords Dance
---
Poliwrath (M) @ Leftovers
Ability: Water Absorb
EVs: 252 HP/80 Atk/32 Spd/144 SDef
Careful nature (+SDef, -SAtk)
- Waterfall
- Bulk Up
- Rest
- Sleep Talk
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So heres the deal. Mono-fighting NEEDS stealth Rock to help vs. Flying pokemon, so Infernape was relegated to that role. Breloom has status that is good for the team so he was thrown in there. Machamp is the lure for Lucario to sweep, and Poliwrath patches up fire weaknesses while adding a late-game win condition (basically, if I eliminate your Rotom / Celebi / Zapdos, Poliwrath has a chance to win it for me even if your destroying me). Hitmontop is the safety to revenge things that may be troublesome (Infernape destroys the team for example without Hitmontop). While this team is FAR from perfect, I would estimate it wins about 2 out of 3 games.
Other things I considered after initial testing was that my Infernape set had to be tailored to beat Azelf, otherwise I could easily be 6-0ed. Also, found Double Status Breloom to be amazing because he puts something to sleep with Spore, than his main counter is usually Salamence or Gyarados or something becomes much less threatening to the team when paralyzed on the switch. Remember, everything is a unit.
With that being said, I'm working on a mono-water team with Crocune as win condition and Lanturn being that safety pokemon.. still not completely sure yet.