Here is a small list of sites about Magento that I find interesting, and recommend them to developers who want to learn more about Magento.
All those sites and articles are a valuable addition and good source for Magento knowledge.
Some links are from official sites, which are frequently updated.
Other links are from private blogs and pages of experienced Magento developers who love sharing knowledge.
Adobe Commerce Official Documentation: http://www.magentocommerce.com/knowledge-base/
System requirements for the latest Magento 2 releases: System requirements
The ExtensionsMall Blog: http://www.extensionsmall.com/
The Swiss army knife for Magento: n98-Magerun2