Great Guide. Some random things to consider adding.
Colossus also gives a free trader unit, which makes their +1 trade route capacity all the more immediately useful. (Great Zimbabwe does not provide a free trader unit -- you have to build that one.)
Civic/Policy boosts to trade route yields or other Trade-route-related bonuses:
Caravanasaries (Ancient Era policy) = +2 Gold from all Trade Routes. Unlocked at Foreign Trade (Ancient Era civic) and obsoleted by Triangular Trade (Renaissance Era policy)
Triangular Trade (Renaissance Era policy) - +4 Gold and +1 Faith from all Trade Routes. Unlocked by Mercantilism (Renaissance Era civic) and obsoleted by Ecommerce (Information Era policy)
Ecommerce (Information Era policy) = +5 Production and +10 Gold from international Trade Routes. Unlocked by Globalization (Information Era civic).
Trade Confederation (Medieval Era policy) = +1 Culture and +1 Science from international Trade Routes. Unlocked by Mercenaries (Medieval civic) and obsoleted by Market Economy (Modern Era policy)
Market Economy (Modern Era policy) = International Trade Routes provide +1 Gold per Luxury and Strategic Resource improved at destination, as well as +2 Culture and +2 Science. Unlocked by Capitalism (Modern Era civic)
Arsenal of Democracy (Modern Era diplomatic policy) = Trade Routes with an Ally provide +2 Food and +2 Production for both cities. Unlocked at Suffrage (Modern Era civic).
Collectivization (Modern Era policy) = +4 Food from domestic Trade Routes. Unlocked at Class Struggle (Modern Era civic).
Online Communities (Informatoin Era policy) = +50% Tourism to civilizations to whom you have a Trade Route. Unlocked at Social Media (Information Era civic).
City-State-related trade route bonuses:
Carthage (militaristic CS) suzerain bonus = Each Encampment district provides +1 Trade Route capacity.
Amsterdam (trade CS) suzerain bonus = Trade Routes to foreign cities earn +1 Gold for each Luxury resource at the destination.
Kumasi (cultural CS) suzerain bonus = Trade Routes to any city-state provide +2 culture and +1 Gold for every specialty district in the origin city.
Jakarta (trade CS) suzerain bonus = Your Trading Posts in foreign cities earn +1 Gold for each of your Trade Routes passing through.
Lisbon (trade CS) suzerain bonus = Your Trader units are immune from being plundered on water tiles.
You can also pop a free trader unit from a tribal village, but only if you have a free trade route (most commonly happens after you unlock Foreign Trade but haven't yet built your first trader unit).
On civ bonuses, you note part of Rome's trade post bonus, but you might also note the rest of their trade/road-related bonuses and these others:
Rome = All cities start with a Trading Post. If founded within Trade Route range of Rome's capital, they also start with a road to the city. Rome's Trade Routes provide +1 Gold for passing through Trading Posts in Rome's cities.
Cleopatra's Mediterranean's Bride trait = Egypt's Trade Routes to other civilizations provide +4 Gold for Egypt. Other civilizations' Trade Routes to Egypt provide +2 Food for them and +2 Gold for Egypt.
Peter's Grand Embassy trait = Receives Science or Culture from Trade Routes with civilizations that are more advanced than Russia (+1 per 3 technologies or civics ahead).
Spain = Trade Routes between multiple continents receive bonus Gold for routes to other civilizations, and bonus Food and Production for routes between your own cities.
You might want to note that there are some Eureka/Inspiration boosts associated with trade routes:
Currency (Classical Era technology) = boosted by making a Trade Route
Medieval Faires (Medieval policy) = boosted by maintaining 4 Trade Routes
Finally, some additions to the trade-related Great Person list:
John Rockefeller (Industrial Era great merchant) = Grants 1 Oil, a strategic resource. Your Trade Routes gain +2 Gold for each Strategic Resource improved by the destination city. 1 charge.
Raja Todor Mal (Renaissance Era great merchant) = Gain 1 Envoy. Your Trade Routes to your own cities gain 0.5 Gold for each specialty district at the destination. 1 charge.
Sara Breedlove (Modern Era great merchant) = +25% Tourism towards other civilizations you have a Trade Route to. 1 charge.
Ching Shih (Industrial Era great admiral) = +100 Gold. Military units gain +60% reward when plundering sea Trade Routes.
Francis Drake (Renaissance Era great admiral) = +75 Gold. Military units gain +50% reward when plundering sea Trade Routes.
Rajendra Chola (Medieval Era great admiral) = +50 Gold. Military units gain +40% reward when plundering sea Trade Routes.