Sorted alphabetically by last name · 2775 fighters
| Name | Nickname | |
|---|---|---|
| RR | Ronaldo Rodriguez | "Lazy Boy" |
| RR | Ronda Rousey | "Rowdy" |
| R | Rongzhu | "The Yama King" |
| RL | Ronnie Lawrence | "The Heat" |
| RM | Ronny Markes | |
| RJ | Rony Jason | |
| RT | Ronys Torres | |
| RR | Roosevelt Roberts |
| "The Predator" |
| RM | Roque Martinez |
| RM | Rory MacDonald | "Red King" |