I have been working on WordPress plugins development since 2011. I have developed both commercial and non-commercial plugins for wordpress, here are a few to mention: https://codecanyon.net/item/file-manager-plugin-for-wordpress/2640424 Other plugins includes Visual Composer elements inside commercial themes, woocommerce plugins, real estate listing, payment gateways, metaboxes and theme options and addons for file manager, contact form 7 and more.