I work on all the versions of Magento and currently updated myself with Magento 2.2.5 experience.
I primarily work on web-development using MagentoCE and Magento EE.
Other GEMS of the websites I work on are JavaScript, JQuery, PHP, AJAX, Magento CE, Magento EE, GTmetrix, Google PageSpeed Insight, HTML/CSS3, Bootstrap, MediqQuery.
CakePHP, Codeigniter, Zend, etc
Html5, CSS3, jQuery Mobile, LESS, SESS.
* DBMS - MySQL, PostgreSQL, Oracle, MongoDB, Sql server 2005.