Best idea to create wordpress theme which is hotcake and never in market till now

I am ready to create wordpress theme but want to know which idea is best in market and not there in market till now.It should blow everyone’s mind and have all options for end user ,this should be easily acceptable by envato with no other questions asked.What is the best way to start.All ideas are heavily welcome.

I think if anyone knew that then they would be more likely to keep it to themselves!

Good luck nevertheless

There should be lot of ideas but not kept on table which may be gathered here ,thats how startups form and lot others will join envato community.