Gary Jones

If bots are attacking your site by appending <code>/search/a-random-string-or-word</code>, then those pages may be getting indexed by search engines, or populating search logs.
This plugin disables that permalink structure.
Search forms will still work, and the search results page will use the less index-friendly <code>?s=search-term</code> format.

Disable Search Slug

Stops /search/... URLs from working, resulting in a WordPress 404 page not found.

antithesisgr

This plugin allows you to use longer URLs (permalinks), by allowing much more characters in your titles and slug. The important is that this is done in a way that is future compatible with WordPress core updates. 
There is a 200 characters limitation on WordPress core nowadays and this limit is raised to 3000 with the plugin. 
Plugin is always extending the current WordPress core code – your long URLs will work even after WordPress core updates. 
This plugin is really useful especially in non-latin slugs because of the required url escaping that increases the length of your permalinks a lot.
<h4>Features</h4>
<ul>
<li>Upon activation the available slug length (post title) will become 3000, allowing long permalinks.</li>
<li>Required functionality is automatically applied without changing WordPress core files.</li>
<li>Even after core updates, plugin will automatically apply required changes and just keep your long URLs working.</li>
<li>Plugin requires at least MySQL 5.0.3</li>
</ul>

Longer Permalinks

Excellent plugin

Allow long permalinks in your WordPress. Useful especially for using non-latin characters in permalinks.  Respects future relevant core updates.

Disable Search Slug vs Longer Permalinks