masayan

This plugin displays an allow on the right side of your blog. The position of the allow is fixed and whenever you click it, you move back to the top of the page. 
Many thanks to Web-Graphics for the original Javascript.
<h3>Anything else?</h3>
That about does it – enjoy!
–Masayan
http://wp.mmrt-jp.net/
<h3>Special Thanks</h3>
–hiromasa
http://hiromasa.zone.ne.jp/blog/
–tai
http://tekapo.com/st/

WP-Modore

This plugin displays an allow with a ?gBack to Top?h link on the right side of your blog.

shazdeh

Using this plugin you can use WordPress <a href="https://codex.wordpress.org/Conditional_Tags" rel="nofollow ugc">Conditional Tags</a> to enable or disable menu items on the front-end. It works like ‘Widget Logic’ but for menu items.
PLEASE NOTE The conditions are PHP codes that are evaluated using PHP’s “<a href="https://www.php.net/manual/en/function.eval.php" rel="nofollow ugc">eval</a>” function, meaning anyone who has access to the Menu manager in WordPress can execute any code. Be mindful of who has access to the Menu manager.
<h4>Usage</h4>
You must insert conditional tags in the “Visibility” box in the menu item options form. You can use any PHP or WordPress functions to build crazy conditions and logics for menu items. For example, to hide the menu item on homepage you can set the visibility to:
<pre><code>! is_home()
</code></pre>
Show the menu only to logged-in users:
<pre><code>is_user_logged_in()
</code></pre>
Show the menu only to guest visitors:
<pre><code>! is_user_logged_in()
</code></pre>
To show the menu item based on <a href="https://wordpress.org/support/article/roles-and-capabilities/">user capability</a>:
<pre><code>current_user_can( 'manage_options' )
</code></pre>

Menu Item Visibility Control

Control individual menu items' visibility based on your desired condition.

WP-Modore vs Menu Item Visibility Control