I'll give some examples of Pokémon that are specially and physically defensive (or both.)
With the highest Sp Defense and tied higest Defense this thing could arguably be one of the best defensive Pokémon.
Its only really useful ability however is Contrary. A moveset with this ability could be:
- Shell Smash
This is also the set Pimpnite used in one of his sweeps so that is an example of how it works.
Another two Pokémon that have one of the highest in both their designated defences.
Regirock is often used for setting up here is a common set for it:
- Stealth Rocks
- Stone Edge/Earthquake
- Drain Punch
You could also have Regirock hold the Assault Vest and replace Stealth Rocks and Substitute with Ice Punch and Power-Up Punch
Regice however can use this set:
- Ice Beam/Blizzard
- Toxic/Thunder Wave
These are just three examples of defensive Pokémon that can do damage as well.
If you wanted one for just pure stalling then Dusknoir would be a very good choice.
If you would like more just ask and I'll add more sets :)