Rhydon!

It still weak same as gyrados.

I've got a Rhydon with the same moveset and think it is the best one. I just powered him up to 2776! He willbe good against Dragonite and Snorlax (because resistance to normal). You just need to be careful about Steel Wing and Earthquake. He won't be a great defender because of double weakness to water.

I used this one for Dragonites, Snorlax: Stone Edge is fast :) It was always Snorlax counter, at least game suggested that by choosing him very often :) Did you try Cloyster(FB/B) on Dragonites? It got huge CP buff, too.

I'm not sure I would use it against Dragonite. Steel Wing hits him for super effective damage and Mud Slap is Not Very effective. Though... if you happen to find a DB/HB Dragonite in a Gym... well then you are in buisness.

What you do have is the best Snorlax counter in the game right now. Mud Slap a tiny bit faster than Rock Smash so even against Snorlax, Mudslap is better and Stone Edge has better neutral DPS than Earthquake.