| Turrican - health fix and unlimited continue | NinjAkira | Turrican | Action > Platformer | GEN | GP | Improvement | 1.0 | 01 Jun 2019 |
| Twin Cobra/Kyuukyoku Tiger Arcade tiles/sprites/colors | fusaru | Twin Cobra | Action > Shooter | GEN | G | Improvement | 2.00 | 14 Jul 2016 |
| Disable flashing | TEPA6ANT | Twin Cobra | Action > Shooter | NES | G, O | Bug Fix | 1.0 | 29 Sep 2017 |
| Twin Hawk / Daisenpuu arcade style tiles/sprites/colors | fusaru | Twin Hawk | Action > Shooter | GEN | G | Improvement | 1.0 | 11 Feb 2017 |
| Twinbee AC | Messatu | TwinBee | Action > Shooter | NES | G | Improvement | 0.3.2 | 21 Jan 2018 |
| Van-1 | Inventor | TwinBee | Action > Shooter | NES | G | Improvement | 1.0 | 01 Jan 2001 |
| Pop'n TwinBee: Rainbow Bell Adventures - Region Fix | SunGodPortal | TwinBee: Rainbow Bell Adventure | Action > Platformer | SNES | O | Improvement | 1.0 | 21 Jan 2015 |
| Twinkle Tale - Alternate Style | Pyron | Twinkle Tale | Action > Shooter | GEN | G | Improvement | 1.0 | 25 May 2016 |
| Uchuu Senkan Gomora Arcade Colors | fusaru | Uchuu Senkan Gomora | Action > Shooter | GEN | G | Improvement | 1.01 | 18 Feb 2016 |
| Ultima: A New Exodus | ludmeister | Ultima: Exodus | Role Playing | NES | T, GP | Improvement | 1.0 | 17 Jan 2012 |
| Ultima: Touhou of Virtue | DASTARD | Ultima: Runes of Virtue | Role Playing > Action RPG | GB | G, T, GP | Complete | 1.02 | 01 May 2009 |
| Ultimate Mortal Kombat Trilogy | KABAL_MK | Ultimate Mortal Kombat 3 | Action > Fighting | GEN | G, S, L, T, GP, O | Complete | 23 (5125) | 30 Mar 2014 |
| Mortal Kombat Revelations | Smoke | Ultimate Mortal Kombat 3 | Action > Fighting | GEN | G, S, L, T, GP | Complete | 1.00 | 10 Sep 2012 |
| Ultimate Mortal Kombat 3 - Arcade Hack | Nemesis_c | Ultimate Mortal Kombat 3 | Action > Fighting | GEN | G, S, GP | Improvement | 0.6 | 05 Jan 2012 |
| Ultimate Mortal Kombat 3 - Redux | RealGaea | Ultimate Mortal Kombat 3 | Action > Fighting | SNES | G, S | Improvement | 1.1 | 11 Aug 2017 |
| Enable bosses and secret menus | Docrow | Ultimate Mortal Kombat 3 | Action > Fighting | SNES | GP | Improvement | 1.0 | 08 Jun 2019 |
| Uninvited Uncensored | Safaribans, Dragoon ZERO | Uninvited | Adventure | NES | G, T | Improvement | 1.0f | 24 Aug 2010 |
| Uniracers Uncensored | Q | Uniracers | Racing | SNES | T, O | Improvement | 1.0 | 30 Sep 2018 |
| Urban Champion Atarisized | Megafield64 | Urban Champion | Action > Fighting | NES | G | Complete | 2.0 | 15 Jan 2014 |
| Valis++ | Sliver X | Valis: The Fantasm Soldier | Action > Platformer | NES | G, T, GP | Improvement | 1.01 | 12 Jun 2007 |
