Which Sonata version are you on ? And what is the version of your example?
Mine is 2.3, does not look like you can play on that from parameters, but you can override the layout to let only appear the create button.
If you need it for all your admins, you better override the layout from the config. If you need it only for list, or show, or remove only overrides those templates then.
in config.yml:
sonata_admin:
templates:
layout: AppBundle:Layouts:standard_layout_override.html.twig
show: AppBundle:Layouts:show.html.twig
list: AppBundle:Layouts:list.html.twig
delete: AppBundle:Layouts:delete.html.twig
edit: AppBundle:Layouts:edit.html.twig
in that file override that block:
{% block sonata_page_content_header %}
{% block sonata_page_content_nav %}
{% if _tab_menu is not empty or _actions is not empty %}
<nav class="navbar navbar-default" role="navigation">
{% block tab_menu_navbar_header %}
{% if _navbar_title is not empty %}
<div class="navbar-header">
<span class="navbar-brand">{{ _navbar_title|raw }}</span>
</div>
{% endif %}
{% endblock %}
<div class="container-fluid">
<div class="navbar-left">
{% if _tab_menu is not empty %}
{{ _tab_menu|raw }}
{% endif %}
</div>
{% if _actions|replace({ '<li>': '', '</li>': '' })|trim is not empty %}
<ul class="nav navbar-nav navbar-right">
<li class="dropdown sonata-actions">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">{{ 'link_actions'|trans({}, 'SonataAdminBundle') }} <b class="caret"></b></a>
<ul class="dropdown-menu" role="menu">
{{ _actions|raw }}
</ul>
</li>
</ul>
{% endif %}
</div>
</nav>
{% endif %}
{% endblock sonata_page_content_nav %}
{% endblock sonata_page_content_header %}
You should also be able to do it for some admins only overriding defining a specific template for those admins on service definitions like that:
app.admin.product:
class: AppBundle\Admin\ProductAdmin
arguments: [~, AppBundle\Entity\Product, AppBundle:Admin\Product]
tags:
- {name: sonata.admin, manager_type: orm, group: Products, label: Products}
calls:
- [ setTemplate, [edit, AppBundle:Product:edit.html.twig]]
But I can't get that "AppBundle:Product:edit.html.twig" template to delete the list action overriding the same block.
Hope this helps you.