ManualsLib - Just enter the keywords in the search field and find what you are looking for!
WebManuals.aero - Flight Operation Manual Authoring
Dozuki - Dozuki is a web-based tool for creating and distributing step-by-step documentation.
AeroDocs - Digital transformation, flight ops, document management, pilot efb, iPad, manual viewer, collaboration, controlled distribution, intelligent information.
Manuzoid - Repository that includes user manuals for various products
IDMR InForm - Aviation Authoring