Okay, so I was testing another gimmick team (I have 8 on my alt account, and I've revealed two so far, I swear I will reveal more at some point), and let me just say, merciless stockpile toxapex wasn't actually bad.
I thought going into it I would have to choose regenerator eventually but it has actually saved me a lot of times against setup sweepers. You can get up a few stockpiles to stop setup sweepers doing too much damage to you, and in the meantime you can toxic them. Now, that toxic damage may be nice, but they can outboost you and toxapex has crummy damage output right? That's where merciless comes in. Since you do guarenteed critical hits when an opposing mon is poisoned, which you would have done with toxic, you can increase your damage output by 1.5x, especially if you have hex like I did. Combine that with crits ignoring stat changes, and that means something like volc can be stonewalled because they are taking consistent damage from your moves and not decreasing your damage output.
IDK guys, this was a kinda fire set.