I know this question has been answered already, but there is a Pokemon that fits your description perfectly; Clefable
Clefable has nice bulk all around, including HP. It's in OU just like you wanted too. It is only weak to 2 types, Steel and Poison, which are not the most common attacking types. It gets Cosmic Power, which raises both its defences, and Soft-Boiled, which is nice recovery. Plus it's ability Magic Guard makes it not take Toxic or Will O Wisp damage.
Here is the set I recommend;
Ability: Magic Guard
Nature: Bold(+Def, -Atk)
EVs: 252 HP/148 Def/12 Sp. Atk/96 Sp. Def
IVs: 0 Atk
The only thing that this set can't really do much against are Steel and Poison types(the only types it is weak to, ironically).
Hope I helped! ;)