Question: what other professional football leagues are there?
Answer: Fourth American Football League (AFL) First Season: 1960.
All-America Football Conference (AAFC) ... 
United States Football League (USFL) ... 
Second American Football League (AFL II) ... 
World Football League (WFL) ... 
First XFL. ... 
Third American Football League (AFL III) ... 
United Football League (UFL) ...