This simple django app provides a useful admin widget for models using generic foreign keys. The widget renders a dropdown to select the content type, and then renders a "raw foreign key" lookup field, similiar to the admin's raw_id_fields.
To use, simply add admin_genericfk to your INSTALLED_APPS. Then, in your modeladmin, extend the GenericFKMixin, and specify the generic fields to use in generic_raw_id_fields:
from django.contrib import admin
from admin_genericfk import GenericFKMixin
@admin.register(models.TaggedItem)
class TaggedItemAdmin(GenericFKMixin, admin.ModelAdmin):
generic_raw_id_fields = ['content_object']