How to find out what boosts any city has.

To find out the boosts of any city, including your own, simply go to the world map from that city and look at the 2 lower corners and the province above the city.  (It makes a triangle.) When you scroll over these they will be the boosts of that city.

Of course, you can always go to your Main Hall to find out your own boosts.  However, you can't go there while it is being upgraded. This method works all the time.

Finding same boosted cities

To find other cities that have the same boost, you simply go at a diagonal - upper left, lower right - to get to other cities with the exact same boosts as the one you are looking at originally.