Kodo

Slug-Free Permalinks lets you switch selected post types and taxonomies to simple ID based permalink formats.
You can choose between:
<ul>
<li><code>/post/123/</code></li>
<li><code>/post-123/</code></li>
</ul>
The plugin only affects the post types and taxonomies you enable in the settings screen.
Features:
<ul>
<li>Select individual public post types</li>
<li>Select individual public taxonomies</li>
<li>Choose slash or hyphen based ID permalink format</li>
<li>Optionally redirect legacy slug URLs to the current ID based permalink when WordPress can resolve the request</li>
<li>Preserve prefixed permalink bases such as <code>/en/</code> when another plugin adds them</li>
<li>Flush rewrite rules automatically when settings change</li>
</ul>
This plugin is focused on permalink structure only. It does not add content features or front-end UI.
Plugin page (English): https://happas.jp/en/slug-free-permalinks/ 
Plugin page (Japanese): https://happas.jp/slug-free-permalinks/
Development repository: https://github.com/1008k/slug-free-permalinks
This plugin is best suited to new sites, sites still defining their permalink policy, or structured-content use cases where slug management is unnecessary.
If your site already has a large number of published posts and established slug based URLs, review the impact carefully before enabling it. Check existing inbound links, search traffic, social shares, and editorial workflow assumptions.
Known limitations:
<ul>
<li>If a post type slug and taxonomy slug are identical, their ID based rewrite patterns can conflict.</li>
</ul>

Slug-Free Permalinks – Simple ID-Based URLs

Use ID based permalinks for selected post types and taxonomies without managing slugs.

Sergey Biryukov

This plugin is available for reference only. Its functionality has been replaced and extended by <a href="https://wordpress.org/extend/plugins/cyr2lat/" rel="ugc">Cyr-To-Lat</a>.
The original author of this plugin is Anton Skorobogatov, who passed away prematurely in 2007. I decided to make it available for installation through the Plugin Browser/Installer. I take no credit for the creation of this plugin.
Converts Cyrillic characters in post slugs to Latin characters. Very useful for Russian-speaking users of WordPress. 
You can use this plugin for creating human-readable links.
Thanks to Alexander Shilyaev for the idea.

Rus-To-Lat

Converts Cyrillic characters in post slugs to Latin characters.

Slug-Free Permalinks – Simple ID-Based URLs vs Rus-To-Lat