How about Milotic and Snorlax?
They both have excellent defenses and high HP!
If you want Milotic then here it is:
Milotic@Leftovers
Bold nature
Ev's 242 Defense,200 Sp.Attack,42 HP,10 Speed,16 Sp.Defense
Recover
Hypnosis/Mirror Coat/Confuse Ray
Surf
Confuse Ray/Ice Beam
If you want Snorlax then here it is:
Snorlax@Leftovers/Chesto Berry
Careful nature
Ev's 242 Sp.Defense,16 Defense,200 HP,52 Attack
Note:If you don't like the Ev Placement then you change them to your liking.
Body Slam/Return
Curse
Shadow Ball/Rest
Counter/Amnesia
Body Slam is there if you want to cause Paralysis,just so you know.
Other Snorlax Options:
Snorlax@Chesto Berry
Careful nature
Ev's 252 Sp.Defense/HP,6 Defense or Attack
Curse
Rest
Return
Shadow Ball
or
Snorlax@Leftovers
Adamant nature
Ev's 252 Attack/Sp.Defense,6 HP
Curse
Substitute
Focus Punch
Return/Shadow Ball
Then there is Cradily:
Cradily@Leftovers
Careful nature
Ev's 200 Defense/Sp.Defense,110 HP
or: 252 HP/Sp.Defense,6 Defense
Note:Again,if you don't like the Ev placement then change them to your liking.
Confuse Ray
Amnesia/Barrier
Recover
Sludge Bomb/Rock Slide
Cradily can work,but I think other people here can make Cradily a better Pokemon.