Mixed martial arts continues to gain popularity, but UFC isn't the only organization out there. UFC may be the top of the sport, but there are other quality fights out there on a regular basis. Here are the top organizations in the MMA universe.

Ultimate Fighting Championship - UFC

The organization that eventually became the Ultimate Fighting Championship started in 1993 and has taken the lead to push MMA to the forefront.

Along with being the premier MMA organization, UFC is also the largest pay-per-view event provider in the world. UFC often showcases its fighters every weekend via a UFC Fight Night card. Once a month, UFC has a major promotion, like UFC 239 coming up July 6.

Bellator MMA

Although Bellator may never catch up to UFC in popularity, it holds its own in the MMA world and has become extremely popular with seasoned MMA fans.

UFC fight cards often pit a massive favorite against an underdog, much like boxing fight cards, but that is not the case for Bellator cards. For example, at Bellator 222 champion Rory MacDonald is only a -205 favorite over Neiman Gracie at +156 in the main event Friday night.

Bellator is also often the place where former UFC greats end up fighting. On the same Bellator 222 card, Lyoto Machida (-370) will battle Chael Sonnen (+285). Around 2010, Machida and Sonnen were two of the most popular fighters at UFC.

Fighter familiarity has led many MMA fans to turn to Bellator. It helps that CEO Scott Coker wants to work with UFC instead of fighting against UFC.

Absolute Championship Akhmat - ACA

Although unknown to most United States mixed martial arts fans, ACA's popularity continues to rise in Europe.

It has gone so far to publish a set of ideological ideas. One of the ideas is an independent policy, where the organization only makes decisions based on the interests of "athletes and fans."