Probably musharna or lickilicky...
Musharna
Pros: good recovery combo; Dream eater+hypnosis, and good HP(116 base) but okay defenses(85 base def, 95 base spdef)
Cons: Recovery won't work if opponent is immune to sleep or is Dark type, has 3 weaknesses, and a limited movepool.
Lapras
Pros: Big movepool, has refresh for statuses, and good HP(130 base) but average defenses(80 base def, 95 base spdef)
Cons: No good recovery move, has 4 weakness, and mediocre speed.
EDIT
Mandibuzz
Pros: Has roost, Big pecks/overcoat, and good Hp(110 base) and defenses(105 base def, and 95 base spdef).
Cons: Has 3 weaknesses, not good offenses.
Lickilicky
Pros: good defenses(95 base both) and HP(110 base), workable offenses(95 base atk, 90 base spatk), good movepool and 1 weakness.
Cons: Normal type, low speed(but can be utilized for gyro ball), and no good recovery
Dusknoir
Pros: good defenses(135 base both), workable atk, 2 weaknesses
Cons: Bad HP (but as Shx said, Pain split would be a good option for healing), no good powerful STAB move(Shadow punch after STAB is only 90 base).
Altaria
Pros: good defenses(90 base def, 105 base spdef) and average HP(75 base), reliable recovery roost, and wide movepool.
Cons: one 4X weakness, average offenses
Audino
Pros; Average HP(106 base) and defenses(86 base for both), wide movepool.
Cons: low speed, not widely used.