There are 2 repositories under google-sitemap topic.
Library for generating Google sitemap XML files
Google XML Sitemap for Magento 2 helps Google search bots find all every corner on your website to index, bring in potential benefits for your SEO strategy. Also, the HTML sitemap will help users more easily search for information on your site than only use Magento default.
PHP library to get the sitemap. It crawls a whole website checking all internal and external links plus a Search Engine Optimization.
A simple Magento sitemap splitter
A usable PHP sitemap generator for google
Create an XML sitemap that can be submitted to Google, Bing and other search engines to help them crawl your website better.
This module allow you to insert a indicate at google a sitemap
PHP Class to generate a Google Sitemap in various formats (XML - list of URLs, images, news, and video sitemaps); it originally only supported XML. Rewritten from older PHP v5.6 code to v8.2 and retooled to use PHP's XMLWriter extension with about 100 less lines of code. On the dev side, it uses PHPUnit for unit testing.
Added support for Google Images Sitemap Generation in the existing library.