WHMCS - WHMCS is an all-in-one client management, billing & support system for online businesses.
Dameware Remote Everywhere - SolarWinds Dameware Remote Everywhere (DRE) is designed as an affordable and powerful cloud-based remote support tool. It doesn't just connect you to machines, it helps you solve your end users problems fast.
HostBill - HostBill is a powerful and flexible, all-in-one automation, billing, client management and support platform for online businesses.
Getscreen.me - Remote access from a browser. Free trial is available. Simple and easy to use screen sharing software.
Blesta - Blesta is professional client management, billing, and support software.
TSplus Remote Desktop Software - TSplus provides fast and feature-rich Remote Desktop Software for Linux, Windows, and Mac.