Free: Emilyguitar
A simple general-purpose guitar library. It's designed to be easy to use for producers who don't necessarily know a lot about guitars and don't need a whole lot of different articulations, control over left-hand position, note off groups etc. The guitar sampled is an Epiphone Emily the Strange model strung with thick flatwound strings. It's basically an inexpensive SG, but a really cute one. Sure, cute looks might not matter all that much when it comes to samples, but being shallow is fun.
323 24-bit 44.1 kHz wav samples and a 98 MB download. There are six SFZ mappings, including some fake unison and barre chords with the notes spread around in stereo.