The NFL's Cowboys, who unseated Spanish soccer club Real Madrid for top spot on the list in 2017, were valued at $8 billion, a 40% jump compared to last year.
According to Forbes, 30 of the NFL's 32 teams were on the top-50 list of the most valuable teams, which it attributed to the league having the richest media deal in sports worth $112 billion through 2032.
The NFL's New England Patriots ($6.4 billion) and reigning Super Bowl champion Los Angeles Rams ($6.2 billion) rounded out the top three.
Apart from the NFL, the other teams on the list that had a cutoff value of $3.1 billion came from European soccer (eight), the National Basketball Association (seven) and Major League Baseball (five).
The New York Yankees ($6 billion) led the way for MLB and were fourth on the list, the New York Knicks ($5.8 billion) were the top NBA club and sixth on the list while Real Madrid ($5.1 billion), at No. 13, were the most valuable soccer club.
The eight soccer clubs on the list came from the English Premier League (four), Spain's La Liga (two), France's Ligue 1 (one) and Germany's Bundesliga (one).