Modules

Better autocomplete matching.

Tab showing entities referencing the current one.

Configure field validation.

Can check for unique title.

Shows a message, see Unique Field Ajax module for clientside indicator.

Provides a hierarchical select widget for a multi level selection.

Provides an edit link for existing content in autocomplete fields.

Provides a field that combines entity reference and a link.

Flexible form builder with some powerful features like sending emails.

CRUD UI for entity references.

Call actions on referenced entities.

Enable via form display settings.

Only usable via edit form.