Issuetrak - Issue tracking software for help desk and customer service
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Deskun - Deskun is a Help Desk system inside Gmail. It enables you to support customers directly from your mailbox, manage projects, and use free features for Gmail.
Drift - A messaging app that helps you grow your business.
Kapdesk - Kapdesk offers support teams with a helpdesk software to streamline support tasks.
Userlike - Userlike is free live chat software for website and mobile support.