Not sure about the Gulf Coast League... someone will be able to answer.

Here is where our colleciton stands as of today:
So far I have been able to get:

Carolina League (GU)
Pacific Association (GU)
American Association (GU)
South Atlantic League (GU)
Eastern league (GU)
New York-Penn league (New)
2012 Triple A All Star (New)
Coastal Plains League (New)
Federation of Mexican Baseball (New)
Northwestern League (New)
Cape Code League (New)
Italian League (New)
Pacific Coast League (New)

On the way:
Golden League
Atlantic Association

Still Need:
International League
Texas League
Southern League
California League
Florida State League
Midwest League
All the Rookie Leagues
Any Independent Leagues

I have the following to trade:
American Association (New)
Eastern League (New)
South Atlantic League (New)