Sand Stall.

Hippowdon @ Leftovers
Ability: Sand Stream
EVs: 252 HP / 200 Def / 56 SpD
Impish Nature
- Earthquake
- Whirlwind
- Ice Fang
- Slack Off

Celebi @ Life Orb
Ability: Natural Cure
EVs: 232 HP / 240 SpA / 36 Spe
Modest Nature
- Thunder Wave
- Leaf Storm
- Hidden Power [Fire]
- Recover

Suicune @ Leftovers
Ability: Pressure
EVs: 252 HP / 252 Def / 4 Spe
Bold Nature
- Rest
- Sleep Talk
- Calm Mind
- Scald

Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 HP / 180 SpD / 76 Spe
Calm Nature
- Stealth Rock
- Roar
- Lava Plume
- Earth Power

Altaria-Mega @ Altarianite
Ability: Pixilate
Happiness: 0
EVs: 248 HP / 136 Def / 96 SpD / 28 Spe
Impish Nature
- Dragon Dance
- Roost
- Frustration
- Heal Bell

Zapdos @ Leftovers
Ability: Pressure
EVs: 248 HP / 68 SpA / 172 SpD / 20 Spe
Calm Nature
- Roost
- Defog
- Thunderbolt
- Hidden Power [Ice]

Gen 4 Sand Stall

Goal: Wall and Stall until Mega-Altaria or Crocune can sweep

Hippowdon is pretty standard. 56 SpDef lets you live 2 LO hp ice from Landorus. Ice Fang hits Gliscor and Lando which otherwise do whatever they want vs you. Whirlwind is great for phazing especially when the opponent is forced to switch so you can rack up hazard + sandstorm damage. You can run rock on this instead of Ice Fang or Whirlwind, but I feel like its better off left to other pokemon because this thing needs to actually be doing something or it gets worn down without saying much.

Tinkerbell Celebi is an underrated threat in the current meta, especially when Greninja leaves. The Twave support helps Altaria set up, and is a hindrance in general to my opponent. Taunt is viable in this moveslot to stop setup, but twave does the same unless facing mega-slowbro (then Leaf Storm just ohkos or 2hkos). Rocks is viable in this slot but not recommended for this set. HP Fire is kind of crazy. Crazy useful. 2hkos all Ferrothorns (unless occa???? even if) and Scizor. And those things are annoying. Running fire coverage on this also lends a free moveslot for Zapdos so it doesn't have to use Heat Wave which is generally not as effective as desired. In this slot Earth Power can be used to hit Heatran and Magnezone harder, though the team support will generally take care of this. Recover in the last slot is recommended because Natural Cure prevents status and Recover will help after you are worn down from Life Orb. Rest is an option though it is not recommended.

Crocune. Strong, sets up early to break for Altaria or late to end the game. Not much to say. You could run Roar or Ice Beam instead of Calm Mind.

Heatran outspeeds most other Heatrans and offensive Scizors. You could run Taunt > Rocks on this if you run rocks on Celebi or Hippo, which is useful vs opposing stall. Earth Power takes care of opposing Heatran (outspeeding and 2hkoing). Standard.

Mega-Altaria has a great ev spread for not being 2hkod by most physical not very effective moves, including Garchomp's earthquake and Heracross's Rock Blast. Roost and Heal Bell make Altaria a great support pokemon early game and a sweeper with Dragon Dance late game. This pokemon is bulky, and only needs steel type to be removed before sweeping, generally.

Zapdos is specially defensive, which is underrated and a lot less common than physically defensive. This pokemon can live a great number of hits, and provides for the team Defog as a pivotal pokemon. Volt Switch can be used > Thunderbolt for momentum, but it sacrifices damage and reliability if this happens. HP Ice is great for taking out Landorus and Garchomp, though Heat Wave can be used if Ferrothorn / Scizor is particularly troubling, or if Celebi no longer has hp fire. Toxic is another viable option, as well as roar.