';
| Fighter | Nickname | Height | Weight | Association | |
| Allain Desamito | 0'0" (0 m) |
145 lbs (65.77 kg) |
The Alpha One | ||
| Allan Abdalla | 6'0" (1.83 m) |
170 lbs (77.11 kg) |
One A One | ||
| Aloisio Figueiredo | "Paraiba" | 5'10" (1.78 m) |
154 lbs (69.85 kg) |
Eagle One / Ryan Gracie Jiu-Jitsu | |
| Amine Malouche | 6'0" (1.83 m) |
170 lbs (77.11 kg) |
K-One Fitness | ||
| Amirshoh Akhrorzoda | 5'8" (1.73 m) |
145 lbs (65.77 kg) |
Triple One Gym | ||
| Anastacio Barrientos | 0'0" (0 m) |
170 lbs (77.11 kg) |
One Nation | ||
| Anderson Silva Souza | 5'7" (1.7 m) |
135 lbs (61.23 kg) |
One Jiu-Jitsu / Team Sergio | ||
| Andreas Spang | "Sweet Swede" | 6'1" (1.85 m) |
224 lbs (101.6 kg) |
J-Sect MMA / One Kick's Gym | |
| Andres Oviedo | 0'0" (0 m) |
145 lbs (65.77 kg) |
One Nation MMA | ||
| Andrew Borcher | 5'11" (1.8 m) |
155 lbs (70.31 kg) |
One on One Fight Team | ||
| Andriyan Grechkosiy | 0'0" (0 m) |
145 lbs (65.77 kg) |
One Team | ||
| Angie Reinhardt | "Domino" | 5'5" (1.65 m) |
130 lbs (58.97 kg) |
Power of One MMA | |
| Antares Simensis | "Krash Coyote" | 0'0" (0 m) |
185 lbs (83.91 kg) |
One Training Center | |
| Anthony Njokuani | "The Assassin" | 6'0" (1.83 m) |
170 lbs (77.11 kg) |
Janjira Muay Thai / One Kick's Gym / Sergio Penha BJJ | |
| Anthony Castrejon | "Pretty Boy" | 5'6" (1.68 m) |
135 lbs (61.23 kg) |
One Kick's Gym | |
| Anton Prusakov | 6'0" (1.83 m) |
234 lbs (106.14 kg) |
Hooligan Number One Gym | ||
| Anwar Abozaid | 6'1" (1.85 m) |
185 lbs (83.91 kg) |
The One | ||
| Arjay Ortega Bongala | "Little Bones" | 0'0" (0 m) |
135 lbs (61.23 kg) |
The Alpha One | |
| Asadbek Erkinov | "Atom" | 5'9" (1.75 m) |
145 lbs (65.77 kg) |
One Chance / Zayed Club Time | |
| Atul Kushwaha | 5'7" (1.7 m) |
155 lbs (70.31 kg) |
One Punch Club | ||