Alright I finally got around to addressing your request, thank you for your patience. This is a very good stall team, but I see a couple of major issues. The first is that you lack a win condition. WinCons are important to stall for a couple of reasons. Firstly, they help to finish off worn down teams fairly quickly, but also act as Stallbreakers. The problem is that opposing stall teams are on equal ground with you, and thus you only have a 50/50 chance to win. WinCons typically are bulkier, and have methods of avoiding residual damage. Opposing Mega Venusaur cause you massive trouble, easily 6-0'ing your entire team atm. Outside of this, this is a very good OU stall team with little threats, but some of the individual sets need improvement.
The clear weak link on the team is Togekiss, who isn't doing much right now outside of heal bell. As I said you need a win condition, so I suggest
Calm Mind Clefable, who not only acts as an amazing stall breaker and status absorber via Magic Guard, but is bulky enough to weather multiple hits like your other walls, and for that reason plays largely like a stall mon. It is also key in beating HO, as it can put pressure on them not to set up in case you lose Quagsire.
Minor Changes:
Skarmory:
Brave Bird > Taunt, as you have defog so you shouldn't be worried about hazards. More importantly, it prevents you from being Taunt bait, and allows you to win if you have Skarm left as your last pokemon. It also beats the threat Mega Venusaur is to your team I stated earlier with little drawback.
Venusaur:
Leech Seed / Roar / Earthquake > Hidden Power [Fire], as it does near nothing to steel types anyways, and further benefits Heatran who already walls you. Leech Seed and Roar are the epitomes of StallSaur, helping you to phaze to get out sweepers, or to nab chip health along a match. EQ offers far better coverage on steels than HP fire, but if you go with it use Relaxed.
Chansey:
Aromatherapy > Toxic cause I replaced Togekiss, and S-Toss is enough normally.
Cool team!
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Clefable @ Leftovers
Ability: Magic Guard
EVs: 252 Def / 252 HP / 4 SDef
Bold Nature
- Moonblast
- Moonlight
- Flamethrower / Toxic
- Calm Mind