Admin Bar Plugin Switcher is a WordPress plugin (download) that enables quick toggling of activation status of plugins right from the admin bar. It can be helpful to developers who want to quickly see something before and after plugin is activated.
This plugin is a very lightweight, it has no settings, just activate it and it works immediately for any user that has permission to activate/deactivate plugins.
Admin Bar Plugin Switcher is released under the terms of GNU General Public License. It is completely free so if you find it useful you can give something back to author. Your help could be done by giving donation, sending pull request on GitHub, sending bugs and suggestions, promoting plugin in blogs, forums, social networks, and other websites.