TinyText + MiniText + 3Text
I was happy with how few of the PICO-8's sparse resources it used, so I decided to put it on the PICO-8 forum. A forum user rightly pointed out that it violated many rules of thumb for designing good-looking fonts due to the constraints of fitting every character into 3x4 pixels. Thus MiniText was born, where characters are either 3x3 or 3x5 and can hang below the writing line (g, j, p, q, y). It's much prettier and still only uses 5 sprites, though the code is a bit longer.
Another forum user suggested being clever with overlapping characters to reduce the sprite count even more, though this would necessitate longer code (PICO-8 users could pick the font that suits their needs; less sprites or less code). I managed to squash TinyText into 4 sprites and MiniText into just 3, releasing 'LS' (Less Sprites) versions of the fonts. That same forum user (LRP) went one better and condensed the whole 26-character MiniText font into just two 8x8 sprites! They also made a really cool sprite guide so you could see where each character was pulled from in the sprites.
To round things off I decided to make a font that was as small as possible and created 3Text, where every single character is just 3x3 pixels. This font completely replaces the system font (3x5) and includes the characters A-Z 0-9 .,^?():/\="'+-. Since there are many more characters it uses 10 sprites, but actually has the shortest code of all of them. I was going to make an LS version but ran into a PICO-8 string-parsing bug which wouldn't let me have a specific (weird) string of punctuation.
They were all pretty fun to make and it was crazy seeing LRP's two-sprite version of MiniText. The forum thread for all of these is here.