Foreword: I've been sitting on this post for a while, largely because the sheer number of games I had to describe was daunting. I started it back in November, and only finished it now, 6 months later. I think the fact that all of the games are made from either ASCII characters or ZX81 characters was also a factor, as they're all generally a bit less appealing, visually. However, I've finished it now, and as such I'm done with all of the drawings that I've been able to find. I know for a fact that there are a few that I'm missing; if I ever find them at any point, I'll scan them and post them here.
When I was around 10 or 11, a friend of mine had a VTech Precomputer 1000. I don't think I ever used it at the time, but I knew that it had a simple ASCII display, and a BASIC programming language interpreter built-in, so I jumped to the logical conclusion that you could program games for it. I went on to imagine a large number of games where the graphics were made entirely from ASCII characters. I think I was peripherally aware that the Precomputer 1000 only had a single line display, so none of my games were viable, but I didn't let that dissuade me too much. Most of these drawings will be from 1990-1992.
Some years later, I acquired a Sinclair ZX81 emulator for the Atari ST, and was kind of taken with the fact that the machine had no capacity for sprites, meaning that everything in its games was rendered either using ASCII characters or a number of special characters, which took the form of black and grey squares mostly. This reignited my strange penchant for drawing games within extreme graphical limitations, so at some point my ASCII games changed to include the ZX81 character set also. At some point I stopped drawing games in any other format, for reasons that aren't exactly clear to me, but as a result all of the latest games I drew are ASCII or ZX81 games. These probably ran from around 1993 to 1995.