| Name | Description | Year | Manufacturer | Rom | Clone | Sample |
| twinfalc | Twin Falcons | 1989 | Philko (Poara Enterprises license) | | | |
| twinhawk | Twin Hawk (World) | 1989 | Taito Corporation Japan | | | |
| twinhawku | Twin Hawk (US) | 1989 | Taito America Corporation | twinhawk | twinhawk | |
| twinkle | Twinkle (set 1) | 1997 | SemiCom / Tirano | | | |
| twinklea | Twinkle (set 2) | 1997 | SemiCom / Tirano | twinkle | twinkle | |
| twinktmb | Twinkle Tale (bootleg of Mega Drive version) | 1993 | bootleg / Sega | | | |
| twinnet | Netstation PC | 199? | Twinhead | ibm5170 | ibm5170 | |
| twinqix | Twin Qix (Ver 1.0A 1995/01/17, prototype) | 1995 | Taito America Corporation | | | |
| twins | Twins (newer) | 1993 | Ecogames | | | |
| twinsa | Twins (older) | 1993 | Ecogames | twins | twins | |
| twinsed1 | Twins (Electronic Devices license, older) | 1994 | Ecogames (Electronic Devices license) | twins | twins | |
| twinsed2 | Twins (Electronic Devices license, newer) | 1994 | Ecogames (Electronic Devices license) | twins | twins | |
| twinspri | Twinkle Star Sprites | 1996 | ADK / SNK | neogeo | | |
| twinsqua | Twin Squash | 1991 | Sega | | | |
| twocrude | Two Crude (US FT revision 1) | 1990 | Data East USA | cbuster | cbuster | |
| twocrudea | Two Crude (US FT version) | 1990 | Data East USA | cbuster | cbuster | |
| twotiger | Two Tigers (dedicated) | 1984 | Bally Midway | | | twotiger |
| twotigerc | Two Tigers (Tron conversion) | 1984 | Bally Midway | twotiger | twotiger | |
| twrshaft | Tower & Shaft | 2003 | Aruze | aleck64 | | |
| twsoc96 | Tecmo World Soccer '96 | 1996 | Tecmo | neogeo | | |
| twsoc98 | Tecmo World Soccer '98 (JUET 980410 V1.000) | 1998 | Tecmo | twcup98 | twcup98 | |
| twst_300 | Twister (CPU 3.00, display A3.01) | 1996 | Sega | twst_405 | twst_405 | genpin |
| twst_404 | Twister (CPU 4.04, display A4.00) | 1996 | Sega | twst_405 | twst_405 | genpin |
| twst_405 | Twister (CPU 4.05, display A4.00) | 1996 | Sega | | | genpin |
| twworld | Wayne's World (Tiger) | 1992 | Tiger Electronics | | | |
| tx0_64kw | TX-0 original demonstrator (64 kWords of RAM) | 1956 | MIT | tx0_8kw | tx0_8kw | |
| tx0_64kw_cpu | MIT Lincoln Laboratory TX-0 64KW | | | | | |
| tx0_8kw | TX-0 upgraded system (8 kWords of RAM, new order code) | 1962 | MIT | | | |
| tx0_8kw_cpu | MIT Lincoln Laboratory TX-0 8KW (new) | | | | | |
| tx0_8kwo | TX-0 upgraded system (8 kWords of RAM, old order code) | 1959 | MIT | tx0_8kw | tx0_8kw | |
| tx0_8kwo_cpu | MIT Lincoln Laboratory TX-0 8KW (old) | | | | | |
| tx0_magtape_image | TX0 Magnetic Tape | | | | | |
| tx0_printer_image | TX0 Typewriter | | | | | |
| tx0_punchtape_image | TX0 Tape Puncher | | | | | |
| tx0_readtape_image | TX0 Tape Reader | | | | | |
| tx1 | TX-1 (World) | 1983 | Tatsumi (Atari/Namco/Taito license) | | | |
| tx1_sound | TX-1 Custom Sound | | | | | |
| tx1j_sound | TX-1 Custom Sound (Japan) | | | | | |
| tx1jb | TX-1 (Japan rev. B) | 1983 | Tatsumi | tx1 | tx1 | |
| tx1jc | TX-1 (Japan rev. C) | 1983 | Tatsumi | tx1 | tx1 | |
| tx4925be | Toshiba TX4925 (big) | | | | | |
| tx4925le | Toshiba TX4925 (little) | | | | | |
| tx8000 | TX-8000 (UK) | 1983 | Texet | laser200 | laser200 | |
| tx81z | TX81Z FM Tone Generator | 1987 | Yamaha | | | |
| txmen | X-Men (Tiger) | 1991 | Tiger Electronics | | | |
| txmenpx | X-Men: Project X (Tiger) | 1993 | Tiger Electronics | | | |
| txsector | TX-Sector | 1988 | Gottlieb | | | genpin |
| txsectorf | TX-Sector (French) | 1988 | Gottlieb | txsector | txsector | genpin |
| txsectorg | TX-Sector (German) | 1988 | Gottlieb | txsector | txsector | genpin |
| tygn | Te Yi Gong Neng (China, V632C) | 1996 | IGS | lhb2 | lhb2 | |
| tylagoon | Typhoon Lagoon (Atronic) | 2002 | Atronic | | | |
| tylz | Tylz (prototype) | 1982 | Mylstar | | | |
| typhoon | Typhoon | 1987 | Konami | ajax | ajax | |
| tz_92 | Twilight Zone (9.2) | 1998 | Bally | | | |
| tz_94ch | Twilight Zone (9.4CH) | 1998 | Bally | tz_92 | tz_92 | |
| tz_94h | Twilight Zone (9.4H) | 1998 | Bally | tz_92 | tz_92 | |
| tz_h7 | Twilight Zone (H-7) | 1994 | Bally | tz_92 | tz_92 | |
| tz_h8 | Twilight Zone (H-8) | 1994 | Bally | tz_92 | tz_92 | |
| tz_ifpa | Twilight Zone (IFPA rules) | 1993 | Bally | tz_92 | tz_92 | |
| tz_l1 | Twilight Zone (L-1) | 1993 | Bally | tz_92 | tz_92 | |
| tz_l2 | Twilight Zone (L-2) | 1993 | Bally | tz_92 | tz_92 | |
| tz_l3 | Twilight Zone (L-3) | 1993 | Bally | tz_92 | tz_92 | |
| tz_l4 | Twilight Zone (L-4) | 1993 | Bally | tz_92 | tz_92 | |
| tz_l5 | Twilight Zone (L-5) | 1993 | Bally | tz_92 | tz_92 | |
| tz_p3 | Twilight Zone (P-3) | 1993 | Bally | tz_92 | tz_92 | |
| tz_p4 | Twilight Zone (P-4) | 1993 | Bally | tz_92 | tz_92 | |
| tz_pa1 | Twilight Zone (PA-1) | 1993 | Bally | tz_92 | tz_92 | |
| tzb215_sprites | Tatsumi TZB215 Rotating Sprites | | | | | |
| tzb315_sprites | Tatsumi TZB315 Rotating Sprites | | | | | |
| u20 | U-20 RS-PCM Keyboard | 1989 | Roland | | | |
| u220 | U-220 RS-PCM Sound Module | 1989 | Roland | | | |
| u3911v3 | U3911-V3 | 198? | Uniron | ibm5170 | ibm5170 | |
| ub8830d | UB8830D | | | | | |
| uballoon | Ultra Balloon | 1996 | SunA (Unico license) | | | |
| uboat | U-Boat | 1982 | Bandai | | | |
| uboat65 | U-boat 65 | 1988 | Nuova Bell Games | | | genpin |
| ubox30 | NubSup TV Interactive Extreme u-box / Extreme u-box Game Station 32Bit Interactive System - New 30 | 201? | <unknown> | | | |
| ucb1200 | Philips UCB1200 modem/audio codec | | | | | |
| uccops | Undercover Cops (World) | 1992 | Irem | | | |
| uccopsar | Undercover Cops - Alpha Renewal Version (World) | 1992 | Irem | uccops | uccops | |
| uccopsaru | Undercover Cops - Alpha Renewal Version (US) | 1992 | Irem America | uccops | uccops | |
| uccopsj | Undercover Cops (Japan) | 1992 | Irem | uccops | uccops | |
| uccopsu | Undercover Cops (US) | 1992 | Irem | uccops | uccops | |
| uchitari | Uchitel' arifmetiki (prototype?) | 1991 | Elektronika | | | |
| uchroma68 | Micro Chroma 68 | 1980 | Motorola | | | |
| uchuuai | Mahjong Uchuu yori Ai wo komete (Japan) | 1989 | Nichibutsu | | | |
| ucv102 | UC-V102 (MSX2, Japan) | 1987 | Pioneer | | | |
| ucytokyu | Uchuu Tokkyuu Medalian | 1997 | Sigma | | | |
| ud1344 | Philips UDA1344 Codec | | | | | |
| ud90_070 | Thomson UD 90-070 5.25" single-sided disk drive | | | | | |
| uda1341ts | UDA1341TS DAC | | | | | |
| udance | U-Dance | 2008 | Tiger / SSD Company LTD | | | |
| uecology | Ultimate Ecology (Japan 931203) | 1993 | Capcom | ecofghtr | ecofghtr | |
| ufo_x | UFO-X | 1984 | Playmatic | | | genpin |
| ufo21 | UFO Catcher 21 | 1996 | Sega | | | |
| ufo7 | UFO Catcher 7 | 2001 | Sega | | | |
| ufo800 | UFO Catcher 800 | 1998 | Sega | | | |
| ufoalac | UFO À La Carte | 1996 | Sega | | | |
| ufombs | UFO Master-Blaster Station | 1979 | Bambino | | | |
| ufomini | UFO Catcher Mini | 1991 | Sega | | | |
| uforobot | UFO Robot (Ver 1.0 Rev A) | 2001 | Nazionale Elettronica | | | |
| ufosensi | Ufo Senshi Yohko Chan (MC-8123, 317-0064) | 1988 | Sega | | | |
| ufosensib | Ufo Senshi Yohko Chan (bootleg, not encrypted) | 1988 | bootleg | ufosensi | ufosensi | |
| ujlnow | Um Jammer Lammy NOW! (Japan, UL1/VER.A) | 1999 | Namco | | | |
| uk101 | UK101 | 1979 | Compukit | sb2m600b | sb2m600b | |
| uk2086 | UK-2086 ver. 1.2 | 1986 | Unipolbrit | spectrum | spectrum | |
| ukiyobox | Ukiyo Box (Japan, v1.3.7) | 1995 | Excellent System | fever13 | fever13 | |
| uknc | UKNC / MS-0511 | 1987 | Elektronika | | | |
| uknc_kmd | UKNC floppy | | | | | |
| ula_next | Spectrum ULA Next | | | | | |
| ula_plus | Spectrum ULA+ | | | | | |
| ultarctc | Ultimate Arctic Thunder | 2001 | Midway Games | | | |
| ultarctcup | Ultimate Arctic Thunder Update CD ver 1.950 (5/3/04) | 2004 | Midway Games | ultarctc | ultarctc | |
| ultennis | Ultimate Tennis | 1993 | Art & Magic | | | |
| ultennisj | Ultimate Tennis (v 1.4, Japan) | 1993 | Art & Magic (Banpresto license) | ultennis | ultennis | |
| ultim809 | Ultim809 | 2010 | Matthew Sarnoff | | | |
| ultra12f | Ultra 12F ESDI Caching Disk Controller | | | | | |
| ultra12f32 | Ultra 12F/32 ESDI Caching Disk Controller | | | | | |
| ultra14f | Ultra-14F SCSI Host Adapter | | | | | |
| ultra24f | Ultra-24F SCSI Host Adapter | | | | | |
| ultra45 | Ultra 45 | 1996 | Sun Microsystems | | | |
| ultracin | Waku Waku Ultraman Racing | 1996 | Sega | | | |
| ultrainv | Ultra Invaders | 1980 | Taito / Konami | invaders | invaders | |
| ultraman | Ultraman (Japan) | 1991 | Banpresto / Bandai | | | |
| ultramhm | Ultra Maru-hi Mahjong (Japan) | 1993 | Apple | | | |
| ultratnk | Ultra Tank | 1978 | Atari (Kee Games) | | | |
| ultrax | Ultra X Weapons / Ultra Keibitai | 1995 | Banpresto / Tsuburaya Productions / Seta | | | |
| ultraxg | Ultra X Weapons / Ultra Keibitai (Gamest review build) | 1995 | Banpresto / Tsuburaya Productions / Seta | ultrax | ultrax | |
| ultrchmp | Se Gye Hweng Dan Ultra Champion (Korea) | 1995 | Nakanihon | nettoqc | nettoqc | |
| ultrchmph | Cheng Ba Shi Jie - Chao Shi Kong Guan Jun (Taiwan) | 1995 | Nakanihon | nettoqc | nettoqc | |
| um486 | UM486/UM486sx | 199? | Elitegroup | ibm5170 | ibm5170 | |
| um486v | UM486V-AIO | 199? | Elitegroup | ibm5170 | ibm5170 | |
| um82c481af | 386 motherboards using the UMC UM82C481AF chipset | 199? | <unknown> | ibm5170 | ibm5170 | |
| um82c491f | 386 motherboard using the UMC UM82C491F chipset | 199? | <unknown> | ibm5170 | ibm5170 | |
| um82c493f | 386 motherboards using the UMC UM82C491F + UM82C493F chipset or BIOTEQ equivalents | 199? | <unknown> | ibm5170 | ibm5170 | |
| um8498f | 486 motherboards using the UMC UM8498F, UM8496F chipset | 199? | <unknown> | ibm5170 | ibm5170 | |
| um8810paio | UM8810 PAIO | 199? | Elitegroup | ibm5170 | ibm5170 | |
| um8886 | 486 motherboards using the UMC UM8886/UM8881 chipset | 199? | <unknown> | ibm5170 | ibm5170 | |
| umanclub | Ultraman Club - Tatakae! Ultraman Kyoudai!! | 1992 | Banpresto | | | |
| umc6619_sound | UMC UM6619 Sound Engine | | | | | |
| umc6650 | UMC UM6650 lockout chip | | | | | |
| umipoker | Umi de Poker / Marine Paradise (Japan, newer) | 1997 | World Station Co.,LTD | | | |
| umipokera | Umi de Poker / Marine Paradise (Japan, older) | 1997 | World Station Co.,LTD | umipoker | umipoker | |
| umk3 | Ultimate Mortal Kombat 3 (rev 1.2) | 1994 | Midway | | | |
| umk3r10 | Ultimate Mortal Kombat 3 (rev 1.0) | 1994 | Midway | umk3 | umk3 | |
| umk3r11 | Ultimate Mortal Kombat 3 (rev 1.1) | 1994 | Midway | umk3 | umk3 | |
| unclepoo | Uncle Poo | 1983 | Diatec | | | |
| undefeat | Under Defeat (Japan) (GDL-0035) | 2005 | G.Rev | naomigd | | |
| undoukai | The Undoukai (Japan) | 1984 | Taito Corporation | fieldday | fieldday | |
| undrfire | Under Fire (World) | 1993 | Taito Corporation Japan | | | |
| undrfirej | Under Fire (Japan) | 1993 | Taito Corporation | undrfire | undrfire | |
| undrfireu | Under Fire (US) | 1993 | Taito America Corporation | undrfire | undrfire | |
| unga | Unga | 198? | <unknown> | special | special | |
| uni386w | 386W 367C REV 1.0 | 199? | UNICHIP | ibm5170 | ibm5170 | |
| uni4800 | 486 motherboards using the UNI4800 chipset | 199? | <unknown> | ibm5170 | ibm5170 | |
| uniap2en | Unitron AP II (in English) | 1982 | Unitron Eletronica | apple2 | apple2 | |
| uniap2pt | Unitron AP II (in Brazilian Portuguese) | 1982 | Unitron Eletronica | apple2 | apple2 | |
| uniap2ti | Unitron AP II+ (Teclado Inteligente) | 1984 | Unitron Eletronica | apple2 | apple2 | |
| unichamp | Champion 2711 | 1977 | Unisonic | | | |
| unicornd | Unicorn Dreaming (0100791V, NSW/ACT) | 1999 | Aristocrat | aristmk5 | | |
| unicornda | Unicorn Dreaming (0100813V, NSW/ACT) | 1999 | Aristocrat | unicornd | unicornd | |
| unicorndnz | Unicorn Dreaming (0101228V, New Zealand) | 2000 | Aristocrat | unicornd | unicornd | |
| unicorndu | Unicorn Dreaming (BHG1584, US) | 2001 | Aristocrat | unicornd | unicornd | |
| unior | Unior | 19?? | <unknown> | | | |
| unistar | Unistar 200 Terminal | 198? | Callan Data Systems | | | |
| unitron | Mac 512 | 1985 | bootleg (Unitron) | macplus | macplus | |
| uniwars | UniWar S | 1980 | Irem | | | |
| uniwarsa | UniWar S (bootleg) | 1980 | bootleg (Karateco) | uniwars | uniwars | |
| uniwb4407 | 486 WB 4407 REV 1.0 | 199? | UNICHIP | ibm5170 | ibm5170 | |
| unk128vt | unknown VT369 based 128-in-1 (GC31-369-20210702-V2) | 2021 | <unknown> | | | |
| unk1682 | unknown VT1682-based 101-in-1 handheld (PAL) | 200? | <unknown> | | | |
| unk2019hh | unknown VTxx based GameBoy style handheld (2019 PCB) | 2019 | <unknown> | | | |
| unk2020hh | unknown VTxx based GameBoy style handheld (2020 PCB) | 2020 | <unknown> | unk2019hh | unk2019hh | |
| unk820501 | unknown Cirsa slot machine on 820501 A PCB | 1982? | Cirsa | | | |
| unk960606 | unknown 960606-5 based machine (set 1) | 2001? | Unidesa/Cirsa | | | |
| unk960606b | unknown 960606-5 based machine (set 2) | 2001? | Unidesa/Cirsa/Europea | | | |
| unkanyw | unknown AnyWorks / Sega medal game BIOS | 2010 | AnyWorks / Sega | | | |
| unkbel | unknown Belatra slot machine | 200? | Belatra | | | |
| unkbpmed | unknown Banpresto medal game | 200? | Banpresto | | | |
| unkbubsc | unknown bubble soccer game | 198? | <unknown> | | | |
| unkch1 | New Cherry Gold '99 (bootleg of Super Cherry Master) (set 1) | 1999 | bootleg | scmaster | scmaster | |
| unkch2 | Super Cherry Gold (bootleg of Super Cherry Master) | 1999 | bootleg | scmaster | scmaster | |
| unkch3 | New Cherry Gold '99 (bootleg of Super Cherry Master) (set 2) | 1999 | bootleg | scmaster | scmaster | |
| unkch4 | Grand Cherry Master (bootleg of Super Cherry Master) | 1999 | bootleg | scmaster | scmaster | |
| unkct | unknown Cointek game | 1989 | Cointek Enterprise Corp | | | |
| unkfr004 | unknown game on FR004 hardware (set 1) | 200? | Nova Desitec | | | |
| unkfr004a | unknown game on FR004 hardware (set 2) | 200? | Nova Desitec | unkfr004 | unkfr004 | |
| unkfr004b | unknown game on FR004 hardware (set 3) | 200? | Nova Desitec | unkfr004 | unkfr004 | |
| unkfr004c | unknown game on FR004 hardware (set 4) | 200? | Nova Desitec | unkfr004 | unkfr004 | |
| unkfr009 | unknown game on FR009 hardware | 200? | Nova Desitec | | | |
| unkgolf | unknown golf game | 19?? | <unknown> | | | |
| unkh8gam | unknown H8 Italian gambling game | 200? | <unknown> | | | |
| unkhockey | unknown Sega air hockey game | 199? | Sega | | | |
| unkhorse | unknown Japanese horse gambling game | 1981? | <unknown> | | | |
| unkhpslt | unknown Hobby Play slot machine | 198? | Hobby Play | | | |
| unkitpkr | unknown Italian poker game | 198? | <unknown> | | | |
| unkkonmd | unknown Konami medal game (game code GS662) | 1997 | Konami | | | |
| unkpacg | unknown 'Pac-Man' gambling game (set 1) | 199? | <unknown> | | | |
| unkpacga | Pucman | 199? | IDI SRL | unkpacg | unkpacg | |
| unkpacgb | unknown 'Pac-Man' gambling game (set 2) | 199? | <unknown> | unkpacg | unkpacg | |
| unkpacgc | Coco Louco | 1988 | <unknown> | unkpacg | unkpacg | |
| unkpacgd | unknown 'Pac Man with cars' gambling game | 1988 | <unknown> | unkpacg | unkpacg | |
| unkpmc | unknown PMC game | 1975? | PMC | | | |
| unkpoker | unknown 1980 poker game | 1980? | <unknown> | | | |
| unkra200 | 200 in 1 Retro Arcade | 201? | <unknown> | mc_tv200 | mc_tv200 | |
| unksig | unknown 'Space Invaders' gambling game (encrypted, set 1) | 199? | <unknown> | | | |
| unksiga | unknown 'Space Invaders' gambling game (encrypted, set 2) | 199? | <unknown> | unksig | unksig | |
| unksigb | unknown 'Space Invaders' gambling game (unencrypted) | 199? | <unknown> | unksig | unksig | |
| unksmk | unknown SMK game | 200? | High Video | | | |
| unktax | unknown TAX game | 200? | TAX / Game Revival | | | |
| unktop | unknown Top game | 19?? | <unknown> | | | |
| unkts | unknown game on TrueSys hardware | 200? | <unknown> | | | |
| unkzilec | unknown Zilec game on Blue Print hardware | 198? | Zilec Electronics / Exodis | | | |
| unomedal | UNO the Medal | 2009 | Sega | segasp | | |
| unsp | SunPlus u'nSP (ISA 1.0) | | | | | |
| unsp_11 | SunPlus u'nSP (ISA 1.1) | | | | | |
| unsp_12 | SunPlus u'nSP (ISA 1.2) | | | | | |
| unsp_20 | SunPlus u'nSP (ISA 2.0) | | | | | |
| unsquad | U.N. Squadron (USA) | 1989 | Capcom | | | |
| untoucha | Untouchable (Ver. 2.10) | 1987 | Dynax | | | |
| uopoko | Puzzle Uo Poko (World) | 1998 | Cave (Jaleco license) | | | |
| uopokoj | Puzzle Uo Poko (Japan) | 1998 | Cave (Jaleco license) | uopoko | uopoko | |
| upc82c710 | Universal Peripheral Controller 82C710 | | | | | |
| upc82c711 | Universal Peripheral Controller 82C711 | | | | | |
| upd1771c | NEC uPD1771C | | | | | |
| upd1990a | uPD1990A RTC | | | | | |
| upd3301 | NEC uPD3301 | | | | | |
| upd4701a | uPD4701A Incremental Encoder | | | | | |
| upd4990a | uPD4990A RTC | | | | | |
| upd4991a | NEC uPD4991a parallel RTC | | | | | |
| upd4992 | uPD4992 RTC | | | | | |
| upd546 | NEC uPD546 | | | | | |
| upd552 | NEC uPD552 | | | | | |
| upd553 | NEC uPD553 | | | | | |
| upd557l | NEC uPD557L | | | | | |
| upd650 | NEC uPD650 | | | | | |
| upd65031 | NEC uPD65031 | | | | | |
| upd65043gfu01 | NEC uPD65043GF-U01 | | | | | |
| upd7001 | NEC uPD7001 A/D Converter | | | | | |
| upd7002 | uPD7002 ADC | | | | | |
| upd7004 | UPD7004 A/D Converter | | | | | |
| upd71071 | NEC uPD71071 DMA Controller | | | | | |
| upd7201 | NEC uPD7201 MPSC | | | | | |
| upd72065 | NEC uPD72065 FDC | | | | | |
| upd72067 | NEC uPD72067 FDC | | | | | |
| upd72069 | NEC uPD72069 FDC | | | | | |
| upd7220 | NEC uPD7220 | | | | | |
| upd7220a | NEC uPD7220A | | | | | |
| upd7227 | NEC uPD7227 | | | | | |
| upd7261 | NEC uPD7261 Hard-Disk Controller | | | | | |