One of the ThreeBSD's. NetBSD's goal in life is to be ported to your toaster, and everything else too. If you have some obscure hardware somewhere, NetBSD probably runs on it, or theres someone trying to port it to it.
NetBSD was the first of "the 3", developed from 386BSD code in the early/mid 80s. FreeBSD and OpenBSD forked from NetBSD.
15 pages link to NetBSD:
