Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Issuetrak - Issue tracking software for help desk and customer service
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community
AzureDesk - Azuredesk.co is an online customer service software and support ticket help desk application for small business and fast-growing companies. Get a free trial today!
HelpScout - Help Scout is a simple, straightforward way to provide excellent support
Kapdesk - Kapdesk offers support teams with a helpdesk software to streamline support tasks.