Tagify
Select and autocomplete widget.
Modules
Simplify
Hide non essential content form fields like publishing options and author.
Field States UI
Configure Form API states in form display settings.
Vertical Tabs Config
Hide vertical tab items per role.
Symfony Mailer
Symfony email subsystem.
Unique Field
Enforce unique field values.
Unique Field Ajax
Validate unique fields using ajax.
Add Content by Bundle Views Area Plugin
Integrated with Form Mode Control.
Similar to Views Add Button.
Allowed Formats
Force text fields to use specific formats.
IE force a paragraph body to use the Minimal text format for restricted HTML.
Entity Tasks
Move entity tasks (IE tabs, view/edit buttons) into a floating block or admin toolbar.
Other modules: