dtgreene: Are there any decent games that run on non-GNU non-Android Linux systems? For example, do you know of any good games for Alpine Linux?
I think you'll have a lot more trouble with the lack of X than the lack of glibc. I'm not sure I know of any games with source code that depend on glibc. Are there specific games you know of that need it? The main thing I'm sure is at least gcc-dependent is anything that uses assembly for acceleration. Even then it's not necessarily glibc-dependent.
I know that back when I ran a Sharp SL-6000, a few SDL programs worked OK, but they were explicitly ported to that platform. Crimson Fields comes to mind for some reason. They may need some porting work to get running on Alpine. Alpine does include SDL1/2 and Mesa, at least.
In any case, with source code included, any GNU-only libc calls and/or behavior dependencies can be fixed, by you, when you encounter them. You could probably also contribute your fixes back to Alpine, the game's upstream maintainers, or whatever so everyone can benefit.
Otherwise, just stick to the ASCII classics. You won't be getting most of the graphic ports working without X, though, as few used SDL. At least you can have color.