Datasets for Country,States,City with ISO Codes,Lat,Long,Population

Many startups need reference data as a foundation to their database if they want to build a global product-What is the best source for getting an ACCURATE list of country,state,city with data fields like IDD numbers,Countey ISO codes,Lat,Long,Population? So many sources we have found offer half baked datasets that is incomplete or inaccurate. Why don’t YC offer ‘core data’ datasets that startups can use to help build out their products? ... or do they - and we just need to ask? Hints on where to search would be great as we’ve lost weeks putting together data only to find it missing some key cities or has outdated data