Nikolay Bachiyski

Разширението „По български“ помага за по-доброто оформление за публикации на български език.
Засега по следните начини:
<ul>
<li>заменя английските кавички с български: „ и “</li>
<li>слага автоматично български кавички на текст в <q> таг</li>
<li>заменя самотна малка буква й с ѝ (ударена малка буква и, и кратко)</li>
<li>заменя много дългото тире, използвано в английския език (mdash) с дългото тире, използвано в българския (ndash)</li>
</ul>

По български

Помага за по-доброто оформление за публикации на български език

Boyan Raichev

This plugin converts Bulgarian cyrillic characters in slugs and filenames to Latin characters, according to the official rules for transliteration. Cyrillic letters in URLs, while supported, are ugly and when copy/pasted around the internet are often encoded (converted to those ugly URLs looking like %DU^ED%…)
The plugin automatically converts slugs when a post is created or updated. It also automatically will convert cyrillic characters in filenames, upon media upload. The filename conversion can be disabled through wp-config.php
It will also work for Russian permalinks, as it matches all the letters in the Russian alphabet, although the user should have in mind that there are minor differences in the common transliterations rules in the two languages.
<h4>Features</h4>
<ul>
<li>Automatically converts existing post, page and taxonomy slugs when you save them</li>
</ul>

Bulglish Permalinks

This plugin does exactly what it says! 
Perfect! 

Does what it says!

Simple and light, yet powerful and very useful. Includes necessary features only. Works perfectly well, as expected. No issues while using it for years now.

Amazing plugin for the Bulgarian WordPress community

This plugin converts Bulgarian cyrillic characters in slugs and filenames to Latin characters, according to the official rules for transliteration.

По български vs Bulglish Permalinks