Windows Live Mail

Microsoft's multi-account email client

Trillian

A multiplatform chat client

Mail Bomber

One of the best massive email delivery programs

ICQ

Complete instant messaging client integrated with social networks

Zimbra Desktop

Manage all your accounts from the same application

Pirch

One of the most popular IRC clients of its time

Microsoft Outlook

Microsoft's email client

Free Email Extractor

Easily gather email addresses

Visual Chat

Create your own chat channel in 3D

Turbo Mailer

Send mass emails

Chord Scale Generator

All the scales and chords a your reach

Yahoo Mail

Access to your Yahoo email account

IncrediMail

Customize your email's appearance and give your friends a surprise

Outlook Connector

Use your Hotmail accounts straight from Outlook

mIRC

Chat on IRC with this great client

Guitar Tuner

How to tune your guitar or any other string instrument

Facebook Messenger

Chat with your contacts from your desktop

Telefuel

Alternative Telegram client focused on productivity for PCs

WhatSender

Send multiple WhatsApp messages from your PC

LINE

Instant messaging from your PC

WA Web Plus

An extension to use WhatsApp Web with more functions

Messenger for Desktop

Facebook Messenger on your Windows desktop

Windows Live Messenger

The departed Messenger by Microsoft

WeChat

The Windows version of the popular Chinese messaging app

QQ International

The messaging application to communicate at global level

WhatsApp Viewer

Tool to view WhatsApp chats on PC

imo

Talk to your friends from your PC

Signal

Instant messaging and chat app that guarantees anonymity

Telegram Messenger

Telegram's desktop client for Windows

IMVU

Instant messaging and chats in 3D environments

WhatsApp Messenger

The official version of WhatsApp for Windows