I use andale mono it has a dot in the middle of zero. There are plenty of others that have dots and slashes. I wouldn't use a font that didn't.
https://en.wikipedia.org/wiki/Andalé_Mono
edit: I also use monaco which has slashes in zero
https://en.wikipedia.org/wiki/Andalé_Mono
edit: I also use monaco which has slashes in zero
In every monospaced font I know, there is a way to identify 0 (the dot or the slash), but not O which could be easily mistaken for a 0.