They exist and they are all around. You just need to look carefully to see them. Happy New Year: may there be unicorns in yours.
(As previously: most of what follows below was first collected in a continuing twitter thread; any comments without attribution are mine.)
But seriously: by which I mean, medievally-seriously:
It doesn’t get more serious than the British Library, their curators, and their Medieval Manuscripts Blog.
“How many horns does a unicorn have?” (2 November 2017):
“Unicorn cookbook found at the British Library” (1 April 2012):