$Action
$Api
$Component
$componentLabel
$Label
$Label.Site
$ObjectType
$Page
$Profile
$SControl
$Site
$System.OriginDateTime
$User
$User.UITheme and $User.UIThemeDisplayed
$UserRole
The difference between the $User.UITheme and $User.UIThemeDisplayed is that $User.UITheme variable returns the look and feel the user is supposed to see, while $User.UIThemeDisplayed returns the look and feel the user actually sees.
Please check the following link for sample Visualforce page code.