Well if you're using Toxicroak in a rain team then you should really try out the SubPunch set.
Toxicroak @Life Orb
244 HP / 252 Atk / 12 Spe
Substitute / Focus Punch / Sucker Punch / Ice Punch
If used correctly, this Pokemon can wreak havoc to an opponent. Just remember to keep a sub up at all times, since it'll help you. And with a sub up, you won't have to worry about speed issues. And always have rain on. If you know your opponent has their own weather starter, then be sure to take that Pokemon out first.