Well, we can see there are good candidates as 3x3 here, of course.

But as a complete US-ASCII set (94 glyphs instead of 62 here), we never know, in this PUZZLE GAME… ;-)

I won't comment right now on these virtual glyphs (my "3x3_font_grid.xlsb" [version 122(unfinished!) will be the right doc file), since in practice -and your already know-, when you edit a single pixel in a strict 3x3 font, you often have to change one or more glyphs consecutively (esp. to prevent a duplication or serious ambiguity, a 94-glyph * n process which never makes you laugh out loud because of time consuming words/phrases tests – even though I might use a few batched scripts, just at the end).

I'll take your suggestions of 3x3 glyphs into account (in my long lists of 3x3 candidates, in the mentioned spreadsheet that is now worth many dozens of hours of work since the early 2014).

B.t.w., please bear in mind that I never advocated too much for 3-dot wide numerics… (= heavy UC ambiguities.)

:-)