Next to Yoast SEO for WordPress, we've developed Yoast SEO for several other platforms in partnership with some great companies.
In partnership with MaxServ, we've developed Yoast SEO for Magento 2.
We have a full Yoast SEO for TYPO3 module, both free and premium.
We currently do not maintain a Yoast SEO for Drupal, because our relationship with its developer has ended. We're looking at new opportunities here so stay tuned.
If you want to have Yoast SEO for your platform, we'd be happy to assist. We only have a few requirements, read all about them here.