I thought it would be fun to do a dual Nuzlocke run with Sun and Moon for the first run-through (keyword: thought). Yeah... not doing that again....
Also Diamond/Pearl challenges are not easy when the starter you get (via ID) is Piplup or Turtwig and you do not find a Ponyta... (this has not happened to me yet and hopefully never will).
My favorite Nuzlocke challenge is the WonderWedLocke. That was my first challenge that I attempted. It was on Pokemon X and after one of my pairs went down I brought in a male Honedge and a female Wurmple. When the Wurmple evolved into a Cascoon I was very tempted to just get rid of her, but then I started to feel bad and gave her a chance.
Protect/Moonlight/Venoshock/Infestation Dustox are amazing against Team Flare.
One of the rules I use sometimes is every time I defeat a rival/boss/admin/etc I'm allowed to use one Revive. Another rule I do, which is somewhat similar, is Life for a Life, which is basically exchanging a Pokemon that's in the PC (who has fainted either the same amount as the Pokemon you want to keep, or 0 times -for a Pokemon that has fainted once-) for the RIP box instead.
Kind of cruel, but when you lose that one Pokemon (like the Dustox...) and you're depressed (and the Sealeo is going to take 5 hours to train to the level limit and $20,000 in vitamins to get its stats up)
I have found that trading myself Pokemon takes a lot of the fun out of it, so in the future I'm really going to limit it. At least until I attempt a WaffleLocke (no PokeMarts, no PokeCenters) along with not evolving the Pokemon... I will be giving myself a Pick Up Pachirisu, a Druddigon, and a Victini. There will be no level limit for this (because a level 45 Shiny probably wouldn't survive against a level 45 Samurott...). It will mean a lot more training, but thankfully Unova has its encounter rate....