Kingdra

Type Tier
Water / Dragon BL
Statistics
Stat
HP
75
353
Atk
95
288
Def
95
288
SpA
95
288
SpD
95
288
Spe
85
268
Name Item

Sleep Talker

Leftovers
Moveset
~ Rest
~ Sleep Talk
~ Double-edge
~ Surf

Sleep Talk was made for Kingdra. If Surf doesn't do enough to your opponent, use Double-Edge (it puts a decent dent on Snorlax and Blissey). Considering Kingdra's defenses, it's not going to die anytime soon.

Other Options

Ice Beam could help for Grass-types, but it leaves you useless against any special walls. Curse isn't that bad of an option, since Double-edge's power is very nice. Since Kingdra has good defenses, it could Haze decently. DragonBreath and Toxic are novelty at best for status afflictions.

Opinion

Kingdra has good stats, but a horrible movepool. The typing helps, but is a little overrated since it gives no physical STAB. Nevertheless, it can attack from both attack stats decently and it can take a Thunderbolt too. Kingdra is very usable, but also very predictable.

Counters

Snorlax comes into Kingdra with impunity despite Double-Edge and Curses up. Electrics like Raikou and Zapdos aren't scared of Surf and Thunderbolt back. Exeggutor and Celebi resist Surf and use Leech Seed to sap at Kingdra's HP. Slowbro and Cloyster can use STAB Psychic and Ice Beam, respectively, while suffering little damage from Double-edge; use Cloyster with caution, though, because its low Special Defense will cause it to succumb to Surf quickly.