It's hard to live a good life (in the short-medium term at least) if someone has hurt you physically, emotionally or financially. And some repercussions can last a lifetime, like bullying which can mess up your education and self esteem seriously limiting your life choices. So I totally get the urge for revenge - it's natural when someone has taken your power.
But I can't imagine much satisfaction with all the toothbrush in the loo, bum sweat on their cup stuff - they will never know, and unless it poisons them (which hopefully no one means to do), there's no harm done - it is no punishment for them.
For me, they'd have to know I was behind whatever was done, to know I haven't let them 'get away' with hurting me. But I'd also need it to never come back on me and not make me look psycho. Probably not possible.
Upgrading to better partners/jobs is a good one but it's not revenge is it. Unless you are doing it solely to make them jealous and get their reaction, it's just a nice side effect.
I have a vile ex boss and 2 horrid exes that I wish zero success on but I'd never risk their downfall being linked to me.