| Map | Title | Author | Players | |
|---|---|---|---|---|
| DM-UG-SunSpeak3 | UG-SunSpeak3 | Unknown | Unknown | |
| DM-Ultra | Ultra | Unknown | Unknown | |
| DM-Umber | Umber | Jack Farnsworth III, aka Gloryroader | 6 to 16 | |
| DM-Under2 | Under2 | Eric 'Marsfyre' Berger | 2 to 8 | |
| DM-Underground3 | DM-Underground 3 | Unknown | 2 to 8 | |
| dm-undergroundmine | dm-undergroundmine | Unknown | Unknown | |
| DM-Underwash | Underwash | Unknown | Unknown | |
| DM-UntamedFinal | Untamed | Maniacbob | 2 to 4 | |
| DM-UntoldStorage | Untold Storage | Andrew "Mclogenog" Yoder | 2 | |
| DM-UOF-Aero | UOF Aero | Sebastien NOVA | 2 to 8 | |
| DM-UOF-Hibernate | UOF Hibernate | Jonatan "Thrallala" Czapnik | 2 to 6 | |
| DM-UOF-Hidrotrik | UOF Hidrotrik | Odedge | 8 to 16 | |
| DM-UOF-OrbitalFlux | UOF Orbital Flux | Lord Porksword | 4 to 10 | |
| DM-UOF-Peak | UOF Peak | Eric "Bl!tz" Rigard | 4 to 12 | |
| DM-UOF4-NyLevesLegacy | UOF4-NyLeves Legacy | Lord PorkSword | 24-32 | |
| DM-URDARAT01 | DM-URDARAT | Unknown | Unknown | |
| DM-UT1-Tutorial | UT1-Tutorial | Gotenksnath | Unknown | |
| DM-Utopia | DM-Utopia | Unknown | Unknown |