Portable implementation of which(1) in Perl

https://metacpan.org/release/File-Which

Number of source filters for perl5 programs

http://search.cpan.org/dist/Filter/

Perl extension providing access to the GSSAPIv2 library

https://metacpan.org/release/GSSAPI

Handle ISO-3166 country codes

https://metacpan.org/release/Geography-Countries

Perl module for processing argument vectors

https://metacpan.org/release/Getopt-ArgvFile

Perl module for extended processing of command line options

Graph, the Perl module for graph operations

https://metacpan.org/release/Graph

Module to produce HTML 'breadcrumb trails'

https://metacpan.org/release/HTML-Breadcrumbs

Determine the encoding of HTML/XML/XHTML documents

https://metacpan.org/release/HTML-Encoding

High-performance, dynamic web site authoring system

https://metacpan.org/release/HTML-Mason

Perl module for handling CGI HTML paging of arbitrary data

https://metacpan.org/release/HTML-Pager

Perl5 module for parsing HTML documents

https://metacpan.org/release/HTML-Parser

Perl extension for scrubbing/sanitizing html

https://metacpan.org/release/HTML-Scrubber

Perl5 module for strip HTML tag

https://metacpan.org/release/HTML-Strip

Generate HTML tables for CGI scripts

http://www.chime.ucl.ac.uk/~rmhiajp/htmltable/index.htm

Some useful data table in parsing HTML

https://metacpan.org/release/HTML-Tagset

Perl module to use HTML Templates from CGI scripts

https://metacpan.org/release/HTML-Template

Web validation in a Perl object using tidy

https://metacpan.org/release/HTML-Tidy

Collection of modules to manipulate HTML syntax trees

https://metacpan.org/release/HTML-Tree

HTTP Cookie jars

https://metacpan.org/release/HTTP-Cookies

WebDAV client library

https://metacpan.org/release/HTTP-DAV

Simple HTTP server class

https://metacpan.org/release/HTTP-Daemon

Conversion routines for the HTTP protocol date formats

https://metacpan.org/release/HTTP-Date

Representation of HTTP style messages

https://metacpan.org/release/HTTP-Message

Implementation of the HTTP content negotiation algorithm

https://metacpan.org/release/HTTP-Negotiate

Perl extensions for keeping data partially sorted

https://metacpan.org/release/Heap

Lexically scoped subroutine wrappers for Perl

https://metacpan.org/release/Hook-LexWrap

Various IO modules for Perl

http://search.cpan.org/dist/IO/

Perl5 compression modules (bzip2, deflate, gzip, zlib, zip)

https://metacpan.org/release/IO-Compress

Perl module with object interface to AF_INET6 domain sockets

http://search.cpan.org/dist/IO-INET6/

IO::Multiplex - Manage IO on many file handles

https://metacpan.org/release/IO-Multiplex

Drop-in replacement for IO::Socket::INET supporting IPv4 and IPv6

https://metacpan.org/release/IO-Socket-IP

Perl5 interface to SSL sockets

https://metacpan.org/release/IO-Socket-SSL

Simplified Perl5 module to handle I/O on in-core strings

https://metacpan.org/release/IO-String

Flexible I/O Perl5 module that allows manipulation of pseudo-TTYs

http://search.cpan.org/dist/IO-Tty/

IO:: style interface to Compress::Zlib

https://metacpan.org/release/IO-Zlib

Use IO handles with non-file objects

https://metacpan.org/release/IO-stringy

Fast lookup of country codes from IP addresses

https://metacpan.org/release/IP-Country

Run subprocesses with piping and redirection

https://metacpan.org/release/IPC-Run

Simple interface to access shared memory

https://metacpan.org/release/IPC-ShareLite

IPC::Signal - Utility functions dealing with signals

https://metacpan.org/release/IPC-Signal

Database connection caching and organization

https://metacpan.org/release/Ima-DBI

Perl module for getting image information

https://metacpan.org/release/Image-Info

Helper functions for PBM/PGM/PPM image file formats

https://metacpan.org/release/Image-PBMlib

Perl5 module to determine the size of images in several common formats

https://metacpan.org/release/Image-Size

Perl extension to convert to JSON (JavaScript Object Notation)

https://metacpan.org/release/JSON

Perl Wrapper Class for the various JSON classes

https://metacpan.org/release/JSON-Any

JSON::XS compatible pure-Perl module

https://metacpan.org/release/JSON-PP

Perl implementation of JSON-RPC 1.1 protocol

https://metacpan.org/release/JSON-RPC

JSON serialising/deserialising, done correctly and fast

https://metacpan.org/release/JSON-XS