PerlIO::utf8_strict provides a fast and correct UTF-8 PerlIO layer. Unlike Perl's default :utf8 layer it checks the input for correctness.

This module exports a single function: ttie. It ties a variable to a type constraint, ensuring that whatever values stored in the variable will conform to the type constraint. If the type constraint has coercions, these will be used if necessary to ensure values assigned to the variable conform.

Crypt::DES is an XS-based implementation of the DES cryptography algorithm. The module implements the Crypt::CBC interface which has blocksize, keysize, encrypt and decrypt functions.

Bit::Vector is an efficient C library which allows you to handle bit vectors, sets (of integers), "big integer arithmetic" and boolean matrices, all of arbitrary sizes. The package also includes an object-oriented Perl module for accessing the C library from Perl, and optionally features overloaded operators for maximum ease of use. The C library can nevertheless be used stand-alone, without Perl.

Hash::FieldHash provides the field hash mechanism which supports the inside-out technique. It is an alternative to Hash::Util::FieldHash with a simpler interface, higher performance, and relic support.

Config::AutoConf is intended to provide the same opportunities to Perl developers as GNU Autoconf does for Shell developers.

This module allows for anonymous packages that are independent of the main namespace and only available through an object instance, not by name.

This is a meta-package containing specifications for installing all the Test::Run plugins.

List::Compare provides a module to perform comparative operations on two or more lists. Provided operations include intersections, unions, unique elements, complements and many more.

MIME-tools is a collection of Perl5 MIME:: modules for parsing, decoding, and generating single- or multipart (even nested multipart) MIME messages.

Reply is a lightweight, extensible REPL for Perl. It is plugin-based (see Reply::Plugin), and through plugins supports many advanced features such as coloring and pretty printing, readline support, and pluggable commands.

This Perl module provides Unicode normalization forms.

This module verifies if requirements described in a CPAN::Meta object are present.

The package contains the ExtUtils::ParseXS module to convert Perl XS code into C code, the ExtUtils::Typemaps module to handle Perl/XS typemap files, and their submodules.

This module provides convenience methods that let you easily create DateTime::Set objects for various recurrences, such as "once a month" or "every day". You can also create more complicated recurrences, such as "every Monday, Wednesday and Thursday at 10:00 AM and 2:00 PM".

Sys::SigAction is a Perl extension for Consistent Signal Handling.

Term::ProgressBar::Simple tells you how much work has been done, how much is left to do, and estimate how long it will take.

This module exports methods useful for factory classes.

Text::Sprintf::Named provides a sprintf equivalent with named conversions. Named conversions are sprintf field specifiers (like %s or %4d) only they are associated with the key of an associative array of parameters. So for example %(name)s will emit the name parameter as a string, and %(num)4d will emit the num parameter as a variable with a width of 4.

This package allows you to stop processing the entire test suite after the first failure, instead of going all the way through it.

This package provides some basic statistics on numerical vectors. All the subroutines can take a reference to the vector to be operated on.

This package transparently speeds up functions by caching return values, trading space for time.

Devel::CheckBin is a perl module that checks whether a particular command is available.

ExtUtils::Config is an abstraction around the %Config hash. By itself it is not a particularly interesting module by any measure, however it ties together a family of modern toolchain modules.