Possible to add widgets in a dropdown nav

Similar to the style above

Hi there,

that would require a mega menu plugin.

Is there any good free versions?

I am not sure there is a free version that would support that kind of function - the only i am aware of that provide a free option is Max Mega Menu - but as i say not sure it provides that feature.

Alternative options maybe this plugin which allows you to add shortcodes to menus:

https://en-gb.wordpress.org/plugins/shortcode-in-menus/

Not sure it will work in this case and it would probably require some custom development to deal with Mobile responsiveness.