You can now filter by yield types given by resources in a trade route. Resources are just assigned a +1 value if they have a bonus to that yield, not too complicated, so Whales is not weighted stronger than say, Wine in the Modern era, even though Wine gives less. Equally, something like Tobacco that gives 6 if there is a Rail Station is not weighted more, because calculating those requirements is hard.
Once I am more of a UI whiz, I will change from text like Culture or Whales, to the icon they normally have.