Piotr Po

Extend your dashboard help by adding new tabs or replacing old ones. You can add tab for the specific roles and screens.
You can export and import content help.
Go to the settings to be able to post for help.

Better Contextual Help

Sam Hoe

Simple modify WordPress default help content or custom post type help content. Additional one help menu for custom help guide. You also can add dashboard widget. This plugin is more for theme developer.

SH Contextual Help

Simple modify Wordpress default help content or custom post type help content. Additional one help menu for custom help guide.

Better Contextual Help vs SH Contextual Help