On Cliki.net <http://www.cliki.net/Common%20Lisp%20Utilities>, 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.

This is a library for selecting portions of sequences, arrays or data-frames.

This package provides an ANSI CL adaptation of the SBCL mailbox utility.

This package provides a pure-lisp implementation of a DNS client. It can be used to resolve hostnames, reverse-lookup IP addresses, and fetch other kinds of DNS records.

Named readtables is a library that creates a namespace for named readtables, which is akin to package namespacing in Common Lisp.

POLICY-COND provides tools to insert and execute code based on a compiler's OPTIMIZE policy. It also contains a contract-like notion of expectations, which allow dynamic checking or inclusion of various things that should happen depending on compiler policy.

Radiance is a web application environment, which is sort of like a web framework, but more general, more flexible. It should let you write personal websites and generally deployable applications easily and in such a way that they can be used on practically any setup without having to undergo special adaptations.

This Common Lisp library focuses on the small set of basic color manipulations (lightening, compliments, etc.) you might use to generate a color palette for a GUI or web page.

This package provides a Common Lisp Twitter client featuring full API coverage.

This library provides a wrapper type for secret values, to reduce the risk of accidentally revealing them.

Gray streams is an interface proposed for inclusion with ANSI CL by David N. Gray. The proposal did not make it into ANSI CL, but most popular CL implementations implement it. This package provides an extremely thin compatibility layer for gray streams.

Portable Threads (and Scheduled and Periodic Functions) API for Common Lisp (from GBBopen project).

This is a YAML parser and emitter for Common Lisp built on top of libyaml.

This package allows flexible specification of package-local preferences.

CL-LOG is a general purpose logging utility, loosely modelled in some respects after Gary King's Log5. Its features include: logging to several destinations at once, via "messengers", each messenger is tailored to accept some log messages and reject others, and this tailoring can be changed on-the-fly, very rapid processing of messages which are rejected by all messengers, fully independent use of the utility by several different sub-systems in an application, support for messengers which cl:format text to a stream, support for messengers which do not invoke cl:format, timestamps in theory accurate to internal-time-units-per-second.

Wu-Decimal enables convenient, arbitrary-precision decimal arithmetic through a reader macro, #$, and an update to the pprint dispatch table. Wu-Decimal uses the CL rational type to store decimals, which enables numeric functions such as +, -, etc., to operate on decimal numbers in a natural way.

This package provides Common Lisp bindings to GSSAPI, which is designed to provide a standard API to authentication services. The API itself is generic, and the system can provide different underlying implementations. The most common one is Kerberos, which has several implementations, the most common of which is probably Active Directory.

Babel is a charset encoding and decoding library, not unlike GNU libiconv, but completely written in Common Lisp.

This Common Lisp package contains the core math utilities of the Bodge library collection.

bubble-operator-upwards is a function that bubbles an operator upwards in a form, demultiplexing all alternative branches by way of cartesian product.

This is a websocket server for Common Lisp using usockets to be portable between implementations and operating systems. It has a programming interface that allows for multiple websocket apps per server using Common Lisp keywords for different websocket events. It has useful restarts and customizable errors.

simple-neural-network is a Common Lisp library for creating, training and using basic neural networks. The networks created by this library are feedforward neural networks trained using backpropagation.

This package provides a concise, intuitive and flexible macro for trivial lambdas that eschews explicit naming of parameter variables in favor of positional references, with support for a used or ignored &rest parameter and automatic declaration of ignored parameters when logical gaps are left in the positional references. Further convenience features are provided.

This Common Lisp library provides a simple FIFO implementation with no external dependencies.