Freshservice - Freshservice: the one-stop cloud solution for all your IT management needs.
ManualsLib - Just enter the keywords in the search field and find what you are looking for!
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
Manuzoid - Repository that includes user manuals for various products
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
ManualAgent - Manuals and guides