Niche website idea? Nootropics or Doomsday/Survival gear/blog?

I am new to the niche scene and I have been researching and "studying" niche affiliated marketing. The 2 topics I have come too are Nootropics(Fairly new niche, growing industry,ect) or like a doomsday prepping site. You or anyone do any of these topics or know about them? Please give me opinions. Much love.