XFL2020: 2020- (0 seasons)
Successor to the previous XFL, with teams centrally owned and operated by the league with the idea of a faster and simpler style of play
AAF: 2019-2019 (1 season)
Suspended by controlling owner 8 weeks after beginning its first and only season.
Arena: 1987- (33 seasons)
Indoor football played on a field 4x smaller than the NFL, with rules encouraging fast-paced offensive performance.
CFL: 1950- (70 seasons)
Highest level of competition in Canadian football, culminating in the Grey Cup championship game in late November.
UFL: 2009-2012 (4 seasons)
Never had more than five teams and played its games in the fall season in non-NFL markets.
XFL: 2001-2001 (1 season)
Joint venture between the World Wrestling Federation and NBC. Conceived as having fewer rules and encouraging rougher play.
WLAF: 1991-2007 (17 seasons)
Backed by the NFL to serve as a type of spring league. Also known as the World League of American Football (WLAF).
USFL: 1983-1985 (3 seasons)
Attempted to move from a spring to a fall schedule to compete directly with the NFL, effectively ending the league's existence.
WFL: 1974-1975 (2 seasons)
Following an NFL players strike, the WFL was founded with the opportunity to provide players with better contracts.
COFL: 1965-1969 (5 seasons)
Primarily formed by minor-league teams. Lack of a television contract and poor attendance doomed the league.