I'm trying to build a deck that abuses cards like Skyshroud Cutter , by turning that life-gain into life-loss instead. Now I know Rain of Gore only effects cards that your opponents' control, but I'd like to know if there are any cards out there that allow me to hurt my opponents from permanents that I control?
Rain of Gore doesn't work like that. It only works on an ability or spell from its own controller.
If only he didn't state that he knows exactly that in his own original post. That's why he's looking for alternatives that do work the way he wants.
Once you find such a thing, Phelddagrif / Questing Phelddagrif are natural add to the deck. For each W you spend, they gain 2 life, which hopefully you can turn against them. Maybe run Skyshroud Elf s in your deck for their ability to wash all your mana into white as needed (as well as their usual mana-ramping utility).