Slugs for $parent_slug (first parameter)
Dashboard: ‘index.php’
Posts: ‘edit.php’
Media: ‘upload.php’
Pages: ‘edit.php?post_type=page’
Comments: ‘edit-comments.php’
Custom Post Types: ‘edit.php?post_type=your_post_type’
Appearance: ‘themes.php’
Plugins: ‘plugins.php’
Users: ‘users.php’
Tools: ‘tools.php’
Settings: ‘options-general.php’
Network Settings: ‘settings.php’