Well as far as I know some of these games may have fan translations in progress but IDK if their fan translation exist "fully". Also some of these games may have English versions but they are actually cut-content remake versions when their Japanese version is the actual game:
PC:
- Densha De D series (Initial D but train drifting parody lolol)
- Shin Megami Tensei: Imagine (I know that this MMO game is still active via community effort since it was officially shut down, it had English translations that doesn't cover the whole full Japanese content)
- Dragon Quest 10 (It's a MMO game that there is fan English translation effort that would be cool if it was 100%)
PC-98:
- CRW Metal Jacket 2 (Its first game has fan translation but not the 2nd one)
PS1:
- Zero4 Champ DooZy-J (The game wasn't in repo, so it's a street racing simulator game with life sim elements but it just cover drag racing and plays more like a visual novel from time to time. Only one game in this series has English fan-patch)
- Fire Woman Matoigumi (The game wasn't in repo. Basically life and school-sim RPG game)
- Tokyo Majin Gakuen: Kenpūchō (The game wasn't in repo. Basically reminds me of Persona but more like a visual novel with isometric turn-based tactical combat here and there. This series is interesting because similar to Sims games people have emotional states and your character can form relationship with them via emotional decisions so it doesn't simply happen via "right dialogue choices based on words")
Koukidou Gensou: Gunparade March (Japan) PSX ISO Game ID: SCPS-10136. Languages: Japanese. For Sony PlayStation.
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Shiritsu Justice Gakuen: Legion of Heroes (Japan) PSX ISO Game ID: SLPS-01240, SLPS-01241. Languages: Japanese. For Sony PlayStation.
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Shiritsu Justice Gakuen: Nekketsu Seishun Nikki 2 (Japan) PSX ISO Game ID: SLPS-02120. Languages: Japanese. For Sony PlayStation.
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London Seirei Tanteidan (Japan) PSX ISO Game ID: SLPS-01787. Languages: Japanese. For Sony PlayStation.
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Kowloon's Gate: Kowloon Fuusuiden (Japan) PSX ISO Game ID: SLPS-00706, SLPS-00707, SLPS-00708, SLPS-00709. Languages: Japanese. For Sony PlayStation.
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Yuuyami Doori Tankentai (Japan) PSX ISO Game ID: SLPS-02274. Languages: Japanese. For Sony PlayStation.
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PS2:
- Shin Bakusou Dekotora Densetsu (The game wasn't in repo. Basically it's about Japanese truckers who love to modify their trucks visually. That's why the game is filled with Japanese "dekotora" trucker culture as visual novel aspects, truck "wars" you play and then my favorite you can listen to various enka songs while you driving and even your trucks cries or smiles to some enka songs!!! lol)
- Chou Saisoku! Zoku-sha King BU no BU: Bucchigiri Densetsu 2-kai: (The game wasn't in repo. My favourite street racing game after Racing Lagoon and Zero4 Champ series. Instead of ordinary Japanese street racers the game is about zokusha culture that is about crazy modification of cars that no amount of words can describe how crazy these cars looks like!!! lolol)
Kenka Banchou (Japan) PS2 ISO Game ID: SLPM-66035. Languages: Japanese. For Sony PlayStation 2.
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Kenka Banchou 2: Full Throttle (J+English Menus) PS2 ISO Game ID: SLPM-66632. Languages: Japanese. For Sony PlayStation 2.
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(Though gotta say most of the series has no English patch but only its 3rd game was officially released in English)
PSP:
GachiTora! Abarenbou Kyoushi in High School (Japan) PSP ISO Game ID: NPJH-50409. Languages: Japanese. For Sony PlayStation Portable.
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Sega CD:
Shadowrun (Japan) SEGA CD ISO. A RPG game released on 1996 by Compile, Group SNE
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Sega Saturn:
Crows: The Battle Action For Sega Saturn (Japan) Saturn ISO for SEGA Saturn. Genre: Beat 'em up. Published and developed by Athena
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3DS:
- Monster Strike (It's like pokemon but more deep into RPG but its combat style is launching your monster to enemy in slingshot-style combat way)
- Chousoku Henkei Gyrozetter: Albatross no Tsubasa (It's like pokemon but your "pokemon" is a car that can turn in fighter robots!!!!)
- Hamatora: Look at Smoking World (Detective game with action gameplay revolving around young people with superpowers)