What kind of things could a person carry to sell and how if they ever had to forcibly leave?
I read diamonds are worthless second hand.
Solid gold seems legit but not sure if coins or jeweler is best.
I saw something about getting gold chains to trade individual links in a emergency.
Are there any other good tips?
Gold is still the preferred way of storing wealth in many parts of the world. You can just take gold bars with you which should have value anywhere.
Physically get them out might prove to be a challenge as the customs would definitely question your bags of gold.
Gold caps (teeth) painted with white enamel was the method of choice in the past.
There are actually limits to what you can bring into/out of a country.