Traits
Forewarn: Tells you if the opponent carries a 1hko or Super Effective move, but in most cases a smart player will know what moves the opponent is carrying, and therefore this ability is obsolete.
Dry Skin: With Rain on the rise, this can be a useful skill. You heal off of water attacks and get leftovers-par healing from rain, but get a makeshift weakness to fire attacks and take slip damage from Sun. Expect to have Ninetails be a counter for Dry Skin sets, and Politoed to be an ideal partner.
Poison Touch: Adds a 20% chance to Poison on all Physical Attacks Toxicroak uses... and he's a physical sweeper. Oh yeah, that's amazing. I mean, it's not as good as using Toxic / Thunder Wave / Will-o-Wisp / Hypnosis in a good amount of situations, but if those aren't readily available, this is great. If your team has a big amount of status support, you may want Dry Skin, but otherwise, this trait has a lot of use.
The Reaper's Touch
Choice Band/Scarf / Life Orb
Jolly / Adamant (252 Attack, 252 Speed, 4 HP)
Poison Touch
- Poison Jab
- Cross Chop
- Sucker Punch
- Stone Edge / Earthquake / Bullet Punch / Swords Dance (Only if Life Orb is used)
Poison Jab and Cross Chop are Toxicroak's ideal STAB options. Sucker Punch is there to cover Psychic types which normally obliterate Toxicroak (Some people will argue that a solid number of Psychic types are locked in the uber tier and that it's an uncommon type to use, but there are enough new slow Psychic types from 5th Generation to warrant a move slot for this move).
The final slot is pretty versatile. Stone Edge catches Toxicroak's flying weakness. Earthquake is earthquake. Bullet Punch has priority, but it's coverage is inferior to Cross Chop's. Finally, Life Orb variants can take Swords Dance for a nice attack boost.
I have my priorities in order
Choice Band / Life Orb
Brave / Quiet (252 Attack, 252 Special Attack, 4 HP)
Poison Touch / Dry Skin
- Vacuum Wave
- Bullet Punch
- Sucker Punch
- Stone Edge / Earthquake / Venoshock / Poison Jab / Swords Dance / Nasty Plot
Gotta have a gimmick set at some point, though this one is remotely viable. First off, Vacuum Wave covers Toxicroak's lack of Mach Punch, even though it uses its not as high SpAtk (Though this lets it devastate Cloyster). Bullet and Sucker Punch make up your other two priority moves.
For the last slot, Stone Edge and Earthquake offer coverage. Poison Jab has nice power. Venoshock should only be considered on Poison Touch variations, but can get huge power if you hit a poisoned target. Finally, Swords Dance and Nasty Plot offer Atk/SpAtk boosts, but which one you choose should be based on the nature you picked.
Let them melt in the rain
Black Sludge
Jolly / Adamant (252 Attack, 252 Speed, 4 HP)
Dry Skin
- Drain Punch
- Sucker Punch / Poison Jab
- Substitute
- Swords Dance / Bulk Up
A gimmick set in every regard, but also one that is capable of clean sweeps if played right. Without Rain set up though, this set loses a lot of viability, so make sure you have rain support and Dry Skin.
Drain Punch, Black Sludge, and Dry Skin keeps your HP very high at all times. Sucker Punch gives you Fighting/Dark coverage and priority (And a way to fight ghosts) while Poison Jab has more power. Substitutes can be set up easily with all of the recovery options that Toxicroak has. With Substitutes up, you can bolster Toxicroak with Swords Dance or Bulk Up.
Counters
Spiritomb is a great counter for its resistance and immunity to the two STABs of Toxicroak. From there, we have every other ghost type, a good number of Steel types, ideally Skarmory, Metagross, Bonzong, Escavalier, Forretress and Durant. Finally, anything that's faster than it with Psychic attacks. Psychic types come to mind, but pokemon with Extrasensory as an egg move or Psychic for no reason also work for the surprise hit, since Toxicroak will probably anticipate a Psychic on a Psychic type and use Sucker Punch in response. Ninetails screws with Dry Skin variants, and carries a few Psychic attacks to dispose of it.