Unscii is very similar to the old IBM BIOS font, but not exactly (e.g., the zero's crossbar).
As for its variants, the constants are actually unscii_alt, unscii_thin, unscii_fantasy, unscii_mcr & unscii_tall (hadn't noticed before that the documentation is wrong for those [it's pointing to the constant names used by the FBInk CLI instead of the API]).
(c.f.,
http://viznut.fi/unscii/ for more about unscii)
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EDIT: Released 0.11.4 to fix that in the config comments.