Kostas Vrouvas

This plugin adds the WordPress menu from the admin sidebar under the {site-name} menu on the front-end WordPress toolbar.
Feedback is much appreciated.

Front-end Toolbar

This plugin adds all WordPress pages from the admin sidebar under the "site-name" menu on the front-end.

kostyatereshchuk

Admin Menu in Frontend adds an option “Show admin menu when viewing site” to your profile. You can enable this option and see the admin menu on the public pages.
Also, you can close the admin panel with returning to the recently viewed public page.
This solution may be good for content managers but not for frontend developers because admin menu may change the design of some themes.
On this video demonstration you can see how to show admin menu in frontend, hide the admin menu and close the admin panel.
<iframe loading="lazy" class="youtube-player" width="750" height="422" src="https://www.youtube.com/embed/3p6-w2sbkzc?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe>
If you want only “Close admin panel” functionality, you can install <a href="https://wordpress.org/plugins/switcher/" rel="ugc">Switcher</a> plugin.

Admin Menu in Frontend

Works almost perfectly. The only issue I'm having are the sub menu's not showing up in some themes, due to z-index issues. Either the plugin needs to set a real high z-index value for the submenus, or have the option for the site admin to adjust that value.

Overall though, very good, so even with this little problem (easily fixable), I gladly give it 5 stars without any hesitations.

Follow up update:

Ok, I can't fix this with a simple z-index value. However, if I collapse the menu, the sub menus appear, which is a nice compromise I guess. So my guess is that this is a JavaScript issue? Again, the submenu issue happens with some themes, and not all. For example, this plugin works fine with the WP default themes.

Almost perfect.

Admin Menu in Frontend allows you to show admin menu when viewing site.

Front-end Toolbar vs Admin Menu in Frontend