The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- SNK PLD's (12 members)
- SSV (2 members)
- Sammy (7 members)
- Sanritsu (1 member)
- Schematics (193 members)
- Seibu (10 members)
- SemiCom (1 member)
- Semicom (1 member)
- Semicon (1 member)
- Sinclair (1 member)
- Software (1 member)
- Sony ZN-1 (2 members)
- Sony ZN-2 (3 members)
- Suna (2 members)
- Synth (3 members)
- TAD (3 members)
- TCH (3 members)
- TPS System (5 members)
- Taito (124 members)
- Taito F2 (3 members)
- Taito F3 (11 members)
- Taito Hardware ID (35 members)
- Taito PLD's (239 members)
- Taito System SJ (2 members)
- Tamtex (2 members)
- Tatsumi (3 members)
- Tecfri (1 member)
- Technos (7 members)
- Technosoft (1 member)
- Tecmo (11 members)
- Tecmo PLD's (6 members)
- Tehkan (1 member)
- Test Equipment (20 members)
- Toaplan (12 members)
- UPL (2 members)
- Undumped (107 members)
- Unico (1 member)
- Universal (3 members)
- Unknown (2 members)
- Untested (111 members)
- V-System Co. (4 members)
- Video System Co. (9 members)
- Vifico (1 member)
- Visco (1 member)
- Webak (1 member)
- Wintechno (1 member)
- Woodplace Inc. (1 member)
- Yun Sung (1 member)
- Z Soft (1 member)
- Zaccaria (2 members)