| Sega Dreamcast GD |  21 - Two One Model T-46504M | 2001 | Princess Soft |
| Trade Stimulator | 21 Black Jack | 1935 | Jennings & Co., O.D. Chicago, IL, USA |
| Pinball | 21 Black Jack | 19?? | BEM Milano, Italy |
| Fruit Machine | 21 Club | 199? | Barcrest Games |
| PC/MS-Windows pack. | 21 Days Model 607660 | 2017 | Steam Valve Corp. |
| NEC PC-Engine HuCARD | 21 Emon - Mezase Hotel ou!! Model HE93003 | 1994 | NEC Home Electronics, Ltd. |
| Commodore Amiga 500 disk | 21 En | 1988 | Courbois Soft. Beuningen |
| Slot Machine | 21 Gambler | 200? | Barcrest USA IGT Group USA |
| Slot Machine | 21 Gambler | 2005 | IGT International Game Technologies Reno, NV, USA |
| Trade Stimulator | 21 Game | 1944 | ABCO Novelty Co. Chicago, IL, USA |
| Amstrad CPC 464 disk | 21 Jeux d'Or | 1989 | US Gold France Chateauneuf de Grasse, France 13442 |
| Adobe Flash game | 21 Jump Street - Find the Alphabets | 200? | 123bee |
| Pinball | 21 Odds | 1936 | Stoner Mfg. Corp. Aurora, IL, USA |
| PC/MS-Windows pack. | 21 Steps to Soul Model 544820 | 20?? | Steam Valve Corp. |
| Fruit Machine | 21 Up 10p Stake/£2 Jackpot | 1981 | Bell-Fruit Mfg. Co., Ltd. B.F.M. UK |
| Fruit Machine | 21 Up 5p Stake/£1 Jackpot | 1979 | Bell-Fruit Mfg. Co., Ltd. B.F.M. UK |
| Trade Stimulator | 21 Vender | 1934 | Groetchen Tool & Mfg. Co. Chicago, IL, USA |
| Trade Stimulator | 21 Vender | 1934 | Jennings & Co., O.D. Chicago, IL, USA |
| PC/MS-Windows pack. | 21 Model 938520 | 20?? | Steam Valve Corp. |
| PC/MS-Windows pack. | 21+ Model 904990 | 2018 | Steam Valve Corp. |
| Coin-op Misc. game | 21,000 | 193? | Rock-Ola Mfg. Corp. Chicago, IL, USA |
| IBM PC 3.5in. disk | 21-en | 1991 | HVB Soft. |
| Commodore C16 cass. | 21-es | 1986 | Unisoft GMK |
| PC/MS-Windows pack. | 2100 Model 1018090 | 20?? | Steam Valve Corp. |
| Amstrad CPC cass. | 2112 AD | 1986 | Design Design Soft. |
| Sinclair ZX Spectrum cass. | 2112 AD | 1985 | Design Design Soft. |
| Amstrad CPC 464 disk | 2112 AD | 1986 | Design Design Soft. |
| PC/MS-Windows pack. | 2112TD - Tower Defense Survival Model 2223590 | 20?? | Steam Valve Corp. |
| Dedicated Console | 218 in 1 Model BC-19 | 200? | BornKid |
| Arcade Video game | 21c Poker | 2002 | Herb Home Technology Co., Ltd. China |
| Arcade Video game | 21C. Poker II | 2002 | Herb Home Technology Co., Ltd. China |
| PC/MS-Windows pack. |  22 Racing Series Demo Model 1422530 | 20?? | Steam Valve Corp. |
| PC/MS-Windows pack. | 22 Racing Series Model 422890 | 20?? | Steam Valve Corp. |
| Coin-op Misc. game | 22-Man Football | 1922 | Smith, Gordon H. UK |
| Wang 2200 soft. | 2200 Game Package | 197? | Wang Laboratories, Inc. |
| Apple II 5.25 disk | 221B Baker Street | 1986 | Datasoft, Inc. Chatsworth, CA, USA |
| Atari 400/800 disk | 221B Baker Street - Case Library #1 | 1987 | Datasoft, Inc. Chatsworth, CA, USA |
| Atari 400/800 disk | 221B Baker Street - Case Library #2 | 1987 | Datasoft, Inc. Chatsworth, CA, USA |
| Commodore C64 disk | 221B Baker Street Model 15101 | 1986 | Datasoft, Inc. Chatsworth, CA, USA |
| Atari 400/800 disk | 221B Baker Street Model 15105 | 1987 | Datasoft, Inc. Chatsworth, CA, USA |
