Blighty

This plugin monitors installed WordPress plugins on your installation. It notifies the admin (or other email) when updates are available. Plugins can be excluded from monitoring.

Blighty Pluginator

This plugin monitors installed WordPress plugins on your installation for updates and notifies via email when they are available.

simshaun

There’s not much to this plugin. It’s a couple barebones filters that turn off the plugin and theme autoupdate emails.
On WordPress 5.5.0, plugin/theme autoupdate emails are turned off regardless of whether or not they failed.
Since WordPress 5.5.1, emails indicating update failures are allowed through.

Disable Plugin Autoupdate Emails

Getting too many "plugin updated" or "theme updated" emails since WordPress 5.5? This turns them off.

Blighty Pluginator vs Disable Plugin Autoupdate Emails