I'm looking for a Scala library allowing for datatype-generic programming (like Scrap Your Boilerplate, for example). A list of libraries with appropriate links and short descriptions for each one would be a perfect answer.
Well,
Adrian Moors has reimplemented Jeremy Gibbons' Origami programming : The paper. The source.
Bruno Oliveira and Jeremy Gibbons have re-implemented Hinze's Generics for the masses, Lämmel & Peyton-Jones' Scrap your Boilerplate with Class, and Origami Programming, and written a detailed comparison about it. Source here.
Naturally, the Scala Collections library itself can easily be seen as an instance of generic programming, as Martin Odersky explains, if only because of its reliance on implicits, Scala's flavor of Type Classes.