There are quite a few good Sand stallers/ walls, since so many steel types do really well under sand (being immune to buffeting).
Sand also has the best set ups (my opinion). Politoed, Ninetales and Abomasnow gain no defence boosts from their weathers, unlike T-Tar's sp. def boost in sand, and both T-Tar & Hippowdon have very good defensive and offensive stats, while the other 3 set ups have rather mediocre stats in comparison.
Both sand starters also make good walls, and it's not uncommon to see them both on a sand team:
Hippowdon @ Leftovers
Ability: Sand Stream
EVs: 252 HP, 180 Def, 76 Atk
Nature: Impish
- Toxic
- Slack Off
- Earthquake
- Ice Fang/ Stealth Rock
Good HP & defence, along with 112 base attack means that it can successfully wall and deal damage at the same time. Stealth Rock or Ice Fang depending on what you need. Hippowdon doesn't fair well against Politoed/ most rain sweepers since most water moves are special, so watch out for that.
Tyranitar @ Leftovers/ Chople Berry
Ability: Sand Stream
EVs: 180 HP, 180 Sp. Def, 148 Atk
Nature: Careful
- Pursuit
- Crunch
- Stone Edge
- Stealth Rock/ Low Kick
Either Stealth Rock or Low Kick depending what you need on your team. Chople Berry to survive a non-STAB fighting move, e.g. Focus Blast from Gengar, or Leftovers for some HP recovery. T-Tar has a lot of weaknesses, notably the x4 Fighting weakness, but it still makes a good wall due to the boosted Sp. Def in sand. It also has a massive attack stat of 134, meaning it doesn't need EV investment to pack a punch.
Since its typing means it's resistant to Pursuit, it doesn't need to fear Scizor pulling that move on it when switching out.
Brozong @ Leftovers
Ability: Levitate
EVs: 252 HP, 252 Def/ Sp. Def, 4 Sp. Def/ Def
Nature: Sassy/ Relaxed
- Stealth Rock
- Gyro Ball
- Toxic
- Explosion
Another Stealth Rock set up, Bronzong can be either defensive or specially defensive, depending on what your team needs. Nature is set to Sassy/ Relaxed to make full use of Gyro Ball, which will be super-effective against rock types on an opposing sand team, notably Terrakion.
Explosion is a filler move; you can choose either Reflect/ Light Screen in place of it if you want, or even make Bronzong a dual screens set up.
Jellicent @ Leftovers
Ability: Water Absorb
EVs: 252 HP, 180 Sp. Def, 76 Def
Nature: Calm
- Recover
- Will-O-Wisp
- Scald
- Hex
Since a lot of members on a sand team will be weak to a rain team, Jellicent is a good rain counter due to its Water Absorb ability. It also acts as a spin blocker, since your sand team will probably contain Skarmory/ Forretress/ Ferrothorn. Jellicent also walls Keldeo, which is an ever popular choice on rain teams due to its massive Sp. Atk, and Surf that's boosted by rain.
Watch out for Psyshock Starmie & Gengar, and also Terrakion as its Choice Band Stone Edge is very poweful. Scizor can also put a dent in Jellicent if you don't get it burned fast enough.
The two favourite set up Pokemon on sand teams are Forretress & Ferrothorn, both having a x4 weakness to fire but able to wall nearly all of T-Tar's weaknesses.
Both will make good grass counters, though most sun team grass Pokemon carry HP Fire/ Weather ball. Ferrothorn makes a good counter for rain teams due to its grass typing, and Forretress will make a very good Scizor counter. Their fire weakness is walled by T-Tar as well, so they'd make a nice core.
Ferrothorn @ Leftovers/ Shed Shell
Ability: Iron Barbs
EVs: 252 HP, 200 Sp. Def, 56 Def
Nature: Sassy
- Power Whip/ Gyro Ball
- Leech Seed
- Spikes
- Protect
Powerwhip or Gyro Ball for your STAB; the former might be better for facing a rain team, while the latter will take advantage of Ferrothorn's slow speed. Shed Shell is there to get away from Magnet Pull Magnezone.
Ferrothorn & Hippowdon will also make a nice duo, as Hippowdon can take neutral fighting hits (most being physical based), and Ferrothorn can take the Grass/ Water/ Ice hits. There's the awkward fire coverage, since Hippowdon's sp. def isn't that great, but you can also have Jellicent on the team too.
Forretress @ Leftovers
Ability: Sturdy
EVs: 252 HP, 252 Def, 4 Sp. Def
Nature: Relaxed
- Volt Switch
- Stealth Rock
- Spikes
- Rapid Spin
While Forretress also has a x4 fire weakness, I didn't give it Shed Shell because it has no reliable method of recovery. I also has Sturdy, which means it can escape from Magnezone with a Volt Switch if it's at full HP.
Forretress will also act as your spinner, in addition to being a physical wall.
Gliscor @ Toxic Orb
Ability: Poison Heal
EVs: 252 HP, 156 Def, 100 Speed
Nature: Jolly/ Impish
- Toxic/ Fling
- Substitute
- Protect
- Earthquake/ Acrobatics
Fling will be the better option for Acrobatics, and since nothing is immune to a flying move, that might be the better attacking option. However, Fling will only poison one Pokemon (since your Toxic Orb is gone after 1 use), so Toxic + E-Quake will probably make the better stalling combination.
Watch out for fast sweepers like Starmie that can OHKO Gliscor with one Ice Beam (or STAB Water move).
Skarmory @ Leftovers
Ability: Sturdy
EVs: 252 HP, 252 Def, 4 Sp. Def || OR || 252 HP, 252 Sp. Def, 4 Def
Nature: Careful/ Impish
- Spikes
- Roost
- Whirlwind
- Brave Bird
Making Skarmory defensive or specially defensive is your choice; since it already has a massive defence of 140, it's not actually that unreasonable to make it specially defensive. It also helps against a lot of fire & electric moves, since they're mostly special based. It would make a good core with T-Tar, since T-Tar can wall fire moves and take some electric hits, while Skarmory can take the fighting, grass, steel, ground & bug hits.
Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 HP, 252 Sp. Def, 4 Def
Nature:
- Lava Plume
- Roar/ Earth Power
- Protect
- Stealth Rock
While Heatran might not make a good wall at first sight due to having that x4 Ground weakness, it makes a very good pair with Forretress due to its Flash Fire ability. It's also a very good Nintales counter, with access to Earth Power & immune/ resistant to most things Ninetales can throw at it.
You'd need something like Jellicent on the team though in order to counter the fighting & water weakness.
Gastrodon @ Leftovers
Ability: Storm Drain
EVs: 252 HP, 200 Sp. Def, 56 Def
Nature: Calm
- Recover
- Scald
- Toxic
- Earth Power
I usually prefer Jellicent over Gastrodon because of Water Absorb, but Storm Drain's not a bad ability either, though it really shines in doubles rather than singles. Still, it means that Gastrodon has no need for Sp. Atk investment due to its ability. It also has a very good base HP and the benefit of being part ground type, which means it won't be buffted.
It needs to be paired with a steel type like Forretress in order to counter the grass hits though.