Top Alternatives to Adium

Pidgin is a free and open-source multi-protocol instant messaging client designed to connect users across various chat networks with a single application. It's highly extensible through plugins and supports a wide range of protocols including XMPP, ICQ, and IRC.

Tox is a free, open-source, and secure peer-to-peer instant messaging and video calling protocol designed for strong privacy and censorship resistance. It provides end-to-end encrypted communications without reliance on central servers.

Trillian is a versatile, multi-protocol instant messaging client that unifies various communication platforms like IRC, XMPP, and more into a single, user-friendly interface. It's designed for both personal and team collaboration, offering features like encrypted chats, group collaboration tools, and extensive customization options.

Digsby was a multi-protocol instant messaging client that unified connections to various chat networks and social media platforms. It allowed users to manage their conversations and updates from services like Aim, Msn, Yahoo, Twitter, Facebook, and Myspace all within a single, integrated application.

Miranda IM is a lightweight, open-source, multi-protocol instant messaging client designed specifically for Microsoft Windows. Known for its extensibility and resource efficiency, it allows users to connect to various chat networks simultaneously through a flexible plugin-based architecture.

Imo is a free instant messaging and video calling application designed for global reach, prioritizing reliability, particularly in regions with unstable network conditions. It offers features like voice and video calls, chat, group messaging, and various multimedia sharing options.

Facebook Messenger is the official messaging application from Facebook, enabling users to connect with friends and family through text, voice, and video calls, as well as group conversations and media sharing.

Empathy is a versatile multi-protocol messaging client designed for text, voice, and video communication across numerous IM networks. It offers features like file transfers, location sharing, and integration with various services, providing a unified communication experience.

HexChat is a free and open-source Internet Relay Chat (IRC) client. Built upon the foundations of XChat, it offers a robust platform for connecting to various IRC networks and participating in real-time text-based conversations, making it a favored choice for users seeking a reliable and customizable chat experience.

IM+ is a versatile instant messaging application designed to unify communication across multiple platforms. It supports a wide array of popular services, including Google Talk, Twitter DMs, Yahoo!, AIM/iChat, ICQ, Jabber, and even Slack. IM+ simplifies staying connected with friends, family, and colleagues, offering a centralized hub for all your chat needs.

Psi is a robust, open-source instant messaging client built on the XMPP protocol. It's known for its focus on speed, efficiency, and adherence to XMPP standards, offering a clean interface and strong privacy features for secure and reliable communication.

Irssi is a highly customizable command-line IRC client popular among power users and system administrators for its extensibility and efficiency.

Kopete is a versatile, free and open-source instant messaging client designed initially for the KDE Plasma desktop. It distinguishes itself by supporting a multitude of protocols, allowing users to connect to various chat networks from a single application.

ICQ is a veteran instant messaging platform offering a wide range of communication features, including text chat, voice and video calls, screen sharing, and group chats. It aims to provide a reliable and feature-rich messaging experience with a focus on privacy and security.

Gajim is a free and open-source instant messaging client for the XMPP protocol. Built using the GTK+ toolkit, it offers a wide array of features for secure and flexible communication, including encrypted chat, group conversations, multi-protocol support via gateways, and extensive customization options.

Miranda NG is a highly extensible, multi-protocol instant messaging client for Windows. A successor to the popular Miranda IM, it offers a modular architecture supporting numerous chat networks, allowing users to consolidate their conversations into a single interface. It's designed for resource efficiency and deep customization.

Quassel IRC is a powerful, distributed, and cross-platform IRC client designed for continuous connectivity and efficient management of multiple IRC networks and conversations.

Instantbird is a powerful, cross-platform instant messaging client built on Mozilla's XULRunner, leveraging the robust libpurple library from Pidgin. It supports a wide array of instant messaging protocols, offering a unified chat experience.

iMessage is a secure instant messaging service developed by Apple, seamlessly integrated across its ecosystem of devices. It allows users to send text messages, photos, videos, audio messages, and more, with end-to-end encryption for enhanced privacy.

Bitmessage is an open-source peer-to-peer encrypted messaging system designed to provide robust privacy and security. It operates without central servers, ensuring decentralized communication and offering anonymity by design. Ideal for those prioritizing secure and private digital interactions, it leverages strong encryption to protect messages from eavesdropping.

Spark is a free, open-source instant messaging client optimized for businesses and organizations. It integrates seamlessly with Openfire servers and supports a wide range of features including group chat, file transfers, and screen sharing, making it a versatile communication tool.

qutIM is a free and open-source, multi-protocol instant messenger designed for connecting to various networks including ICQ, Jabber, Mail.Ru, IRC, and VKontakte. It offers a unified interface for managing multiple accounts and conversations.

KakaoTalk is a popular mobile messaging service offering free text, voice, and video calls. Primarily used in South Korea, it provides a comprehensive communication platform with features like group chats, stickers, and a strong emphasis on user privacy and security.

WeeChat is a highly customizable, free and open-source command-line based chat client. Designed for efficiency and portability, it supports multiple protocols including IRC and XMPP, making it a versatile tool for connecting to various networks.

Psi+ is a robust, cross-platform XMPP/Jabber client tailored for users who prioritize control, privacy, and extensibility. As a development branch of the classic Psi client, it offers advanced features for secure and customizable instant messaging.

Tencent QQ (QQ) is a versatile instant messaging and social platform widely used in China and expandingglobally. It offers a wide range of communication tools including text chat, voice and video calls, group chats, and file sharing.

Kadu is a free, open-source, multi-platform instant messaging client supporting Gadu-Gadu, XMPP, and related services like Google Talk, providing users with a versatile and extensible communication tool.

Bit Chat is a secure, open-source, peer-to-peer instant messenger platform that prioritizes user privacy and security through robust end-to-end encryption and a decentralized network architecture. It empowers users with direct, encrypted communication, bypassing central servers and enhancing resistance to surveillance and censorship.

Coccinella is a free and open-source, cross-platform XMPP/Jabber client. It offers secure instant messaging, group chat, voice chat, and a unique interactive whiteboard feature. Designed with privacy and security in mind, Coccinella provides encrypted communications and supports various communication protocols for a flexible messaging experience on Windows, macOS, and Linux.

Disa is a unified messaging hub that consolidates conversations from various services like SMS, Facebook, and WhatsApp into a single interface, simplifying communication management.

YakYak is an unofficial desktop client for Google Hangouts, providing a dedicated application experience outside of a web browser with features focused on convenience and improved usability.