Sam Margulies

Ever have one erroneously entered custom field name confuse all of your users and you just can’t figure out how to get rid of it? Delete Custom Fields will let you delete every instance of a custom field from your site. Once your remove a custom field using this plugin it will not appear in your list of custom fields when you edit a post or page.

Delete Custom Fields

Doesn't show all custom fields, though (even if you choose Show Hidden) - would be nice to have them as a list instead of a dropdown, but otherwise it does what it promises.

Works

Remove every instance of a custom field from your site.

Newman

This plugin allows you to hide plugin update notifications for wordpress plugins that you do not want to update. 
 Once this plugin is installed and activated, a link will appear under each plugin with available updates that will allow you to block notifications for that update. Once hidden, a link will appear allowing you to unhide the notifications.
This plugin uses WordPress hooks and filters to hide the notifications.

Plugin Update Hider

This plugin allows you to hide plugin update notifications for wordpress plugins that you do…

Delete Custom Fields vs Plugin Update Hider