Brainstorming for Old Ideas

I have a terrible habit, and that's I get an idea in my head for a scenario, place it on a list, and forget what inspired me to come up with it in the first place! So, in the interest of getting these ones out of the way, I turn to you, my fans, for advice. I need inspiring ideas for these scenarios!

World War III in 2012 - I'm fairly certain I came up with this during the 2012 apocalypse craze. All I know about it is that the flashpoint is Korea, so that WWIII is primarily between China and the United States. No Crimea nonsense, so Russia may be on the Western side this time. The war also stays conventional, with nukes maybe being used by China in desperation at the end. 

War of Rice and Salt - Another "modern warfare" one, where a Sino-Indian war turns into WWIII. 

Don't Fear the Reaper - The Black Death never happens and Europe's population skyrockets. But don't worry: later pandemics and wars solve that problem quickly enough. And...that's it. 

If You Want the Old Battalion - The Spanish Flu kills people and brings them back as zombies. I think I had a communist Germany and a White Russia in this one, but that's all I remember. 

Sans Constantine - A world where Constantine is never born, and presumably another emperor brings Christianity to Rome. 

So, any ideas guys? 

EDIT: It seems that there has been a misunderstanding. I'm not asking people which of these I should do next. I'm asking for ideas on how to work with them.