Creep is quite a small font with glyphs that are 4×7 pixels. It allows for a lot of text on a small area while still being very readable.
The unicode coverage is great and still growing as I am actively maintaining this font (visit the github page). The unicode coverage is already great but if you need something that isn’t there: I’m open for suggestions!
One example of the cool features in creep is that it has a number of characters that are specifically created to make Haskell syntax look way better (also usable for other programming languages).