HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.

HelpScout - Help Scout is a simple, straightforward way to provide excellent support

ManualsLib - Just enter the keywords in the search field and find what you are looking for!

HelpDesk - The easiest help desk system for a team like yours.

Manuzoid - Repository that includes user manuals for various products

Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.