What SaaS should I build now 5 years ago?

Weird title because couldn't phrase it better. Assuming some emerging market that lags behind US by 3-4 years. Which are small/medium SaaS platform ideas that can be developed for those markets? or do you have any advise about how I can go about making such list?

I started coding in 2015, don't really know what was happening before. what was still new in 2015?