The Perfect Plink

This deck concept is to get a Dark Gengar going as soon as possible, and repeatedly use it's Pull In attack to get to the point where all your opponent's Pokemon have exactly 10hp left, which becomes a lot easier by right-sizing the damage with Charity.
Dark Gengar is amazingly self-sufficient in protecting itself by preventing your opponent from attacking by keeping your opponent asleep with it's Pokemon Power Deep Sleep. Since this can be active from the bench, it also helps any of your other Pokemon

This deck concept is to get a Dark Gengar going as soon as possible, and repeatedly use it's Pull In attack to get to the point where all your opponent's Pokemon have exactly 10hp left, which becomes a lot easier by right-sizing the damage with Charity.
Dark Gengar is amazingly self-sufficient in protecting itself by preventing your opponent from attacking by keeping your opponent asleep with it's Pokemon Power Deep Sleep. Since this can be active from the bench, it also helps any of your other Pokemon with sleep attacks as well, which can buy you time to attach the 3 energies required to Dark Gengar to start using Pull In.

Once all of their Pokemon have 10hp left, (could be 2 Pokemon, could be the full 6, as long as it's all of their Pokemon) you instantly win the game with a single Pain Amplifier from Sabrina's Gengar, which you can get to pretty easily, even from a single Sabrina's Gastly with 0 energy attached to it, by using a Pokemon Breeder and attaching just the 1 energy required for Pain Amplifier.

The usual weak spot with Dark Gengar is that after you KO an opponent's Pokemon with a Pull In, your opponent gets to attack Dark Gengar for free the following turn without needing to do any flipping for sleep, but since you're never actually KO'ing anything until the absolute end where you win at once, that helps close that gap, and with a Rocket's Hideout, it has 90hp instead of 70hp.

Special Darkness Energy is in there for Dark Gengar to have more powerful Pull Ins, which decreases the amount of turns required to fill up your opponent's Pokemon with damage to set up for the Pain Amplifier sweep.