There are so many exchanges for all bitcoins and alt coins, that I should list them all on my blog.
Some exchanges come and go (for many reasons, main one seems to be owners tend to be a bit dishonest).
Some exchanges are picky about what coins they will trade on.
So really, just because a coin is not traded on certain exchanges does not mean the coin is going nowhere.
One must take the world view when it comes to coins.
What is popular in the USA may not be popular at all in Europe, and so forth.