There are hundreds if not thousands of Talent Agents that can help you get booked.
How do you spot the difference?
The key is to use IMDB. It is the largest movie database that has information on actors, crews, production companies, studio, casting directors, Talent Agents and many more.
They List every cast and crew that participated in the project. Many of these actors will list who they currently using as representation. Therefore it is a very useful source of information to see which talent agencies are getting their actors BOOKED.
They even ranked them according to their popularity.
IMDB is the goto place to find information about every movie or tv show that is currently being made or already completed.
This video explains how you can use IMDB to find the legit talent agents and which ones are getting their actors BOOKED!