Dawi

This plugin disables the WordPress update notifications, as well as update notifications of different plugins. It is ideal to deliver a complete WordPress and not bother the user with alerts. Silence!
<h4>Please note!</h4>
It’s very important that you keep your WordPress plugins up to date. If you don’t, your blog or website could be susceptible to security vulnerabilities or performance issues. If you use this plugin, you must make sure you keep yourself up to date with new releases of your active plugins and update them as new versions are released.

Silence!

Disables the plugin update checking and notification system.

Johan van der Wijk

This plugin disables all WordPress updates (core, plugins and themes). This can be useful if you have multiple environments such as a live and staging server and you don’t want your users to use the update functionality.
This plugin not only disables the update mechanism for the core, plugins and themes, but it also removes the update menu item from the left navigation menu in the admin dashboard.

Disable Updates for WordPress Core, Plugins and Themes

Disables the WordPress update checking and notification system for all core, plugin and theme updates.

Silence! vs Disable Updates for WordPress Core, Plugins and Themes