On Cliki.net , there is a collection of Common Lisp Utilities, things that everybody writes since they're not part of the official standard. There are some very useful things there; the only problems are that they aren't implemented as well as you'd like (some aren't implemented at all) and they aren't conveniently packaged and maintained. It takes quite a bit of work to carefully implement utilities for common use, commented and documented, with error checking placed everywhere some dumb user might make a mistake.
