Where can I find what LCG's exist?
Since Living Card Game is a trademark of Fantasy Flight Games, you should just be able to check their product page and find out.
You are missing:

Android: Netrunner the Card Game
Star Wars: The Card Game

If you are asking if there are any expandable card games, where there isn't any randomness in the cards you get with each expansion (I.E. This is unlike Magic: the Gathering's Trading/Collectible Card game model, with booster packs that are random so you have no idea what you are getting), then it would be difficult to track. There have been other games using the LCG model, but cannot use the term for Trademark infringement reasons.

Summoner Wars by Plaid Hat Games
Killer Bunnies by Playroom Entertainment